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Electronics Forum / Repair / September 2008Weller WTCPT tip not hot enough
I have a Weller WTCPT soldering station with the stock TC201T handle and PTA7 700 degrees F. tip. It's 15 years old and hasn't seen much action. I was using it a lot 3 years ago but for the past 2 years it's been sitting cold in the garage. The past couple times I've used it lately the tip just didn't seem to get as hot as I remember. You know how it is with equipment you use for a long time, you get to know the behavior and what's normal. When I put the heated tip against the sponge, I barely get much of a sizzle. Solder barely melts but does melt, just barely though. I've gone through the troubleshooting guide Weller provides for this station, all appears normal. I have 27.3VAC from the power unit. Heater element reads 12.9 ohms. The "magnastat" opens and closes when the tip is inserted and removed. Unfortunately the guide doesn't cover a warm tip, only one that's stone cold or too hot. I don't know what else to check. I can hear the tip cycling when I turn on the base. It just seems that the heater doesn't stay on long enough like it used to. Do the tips somehow lose their temperature calibration? Is it time for a new soldering station? Any opinions on the WESD51? Il mittente di questo messaggio|The sender address of this non corrisponde ad un utente |message is not related to a real reale ma all'indirizzo fittizio|person but to a fake address of an di un sistema anonimizzatore |anonymous system Per maggiori informazioni |For more info https://www.mixmaster.it >I can hear the tip cycling when I turn on the base. It just seems that the >heater doesn't stay on long enough like it used to. Do the tips somehow >lose their temperature calibration? Is it time for a new soldering >station? Any opinions on the WESD51? The temperature calibration is via the ferromagnetic slug at the back end of each individual tip. I suppose it's possible that the alloy in the slug can "drift" its transition temperature with time, although I haven't noticed this myself. Try removing your current tip and replacing it with another of the appropriate tip shape and temperature range (they come in 600, 700, and 800 degree Farenheit ratings) and see if this resolves the problem. The tips themselves are not expensive... U.S. dealers seem to have them for around $5 in most shapes. I suppose it's possible that the heater in the handle is giving out, or that oxidation on contacts somewhere is preventing adequate current flow to re-heat the iron.  SignatureDave Platt <dplatt@radagast.org> AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! >I have a Weller WTCPT soldering station with the stock TC201T handle and >PTA7 700 degrees F. tip. It's 15 years old and hasn't seen much action. I [quoted text clipped - 17 lines] >lose their temperature calibration? Is it time for a new soldering >station? Any opinions on the WESD51? Nice mystery. I have about 8 Weller soldering stations with exactly the same configuration. I've never seen that problem. It's usually either stone cold, or seriously overheating. I assume that the thermostat cannot be heard clicking when the iron is running luke warm. Maybe a bit of logic might help. The voltage and resistance that you measured are normal. If there were any excessive resistance in the heater part of the system, such as bad thermostat contacts, bad cord, or bad twist lock connections in the handle, these would heat sufficiently to create noticable damage. Only the high resistance in the xformer area in the base could cause low output, yet still read the correct voltage. It might also be a high resistance thermal fuse or high resistance on/off switch. Perhaps it would be useful to measure the resistances in the base. Ummm... unplug the soldering iron first. When stone cold, I measure 1.5 ohms across the 117VAC power plug and 1.5 ohms across the xformer output pins. My guess(tm) is that you'll find one or the other with a quite different resistance. As for a replacement, I have enough parts to build and/or repair perhaps 10 more WTCPT soldering stations, so I've never needed to consider an alternative. If I need one, I just build one out of junk. Unfortunately, they'er not particularly reliable and require constant thermostat contact cleaning. I've also had heating elements die, thermostat movement jam from corrosion, cords fuse internally, and one xformer short and melt. If you buy something new, buy one that doesn't have any moving parts. SignatureJeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 >>I have a Weller WTCPT soldering station with the stock TC201T handle and >>PTA7 700 degrees F. tip. It's 15 years old and hasn't seen much action. I [quoted text clipped - 48 lines] > xformer short and melt. If you buy something new, buy one that > doesn't have any moving parts. Lead Free Solder in use? http://webpages.charter.net/jamie_5" >Lead Free Solder in use? Ummm.... He said: "When I put the heated tip against the sponge, I barely get much of a sizzle. Solder barely melts but does melt, just barely though." If it doesn't boil water, it's not going to melt solder. I use a PTA7 (370C) tip with the evil lead-free solder. It's not the best, but it sorta works. A PTA8 (430C) tip works much better but I've been burning up a tip every 3 months or so. SignatureJeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 >I use a PTA7 (370C) tip with the evil lead-free solder. It's not the >best, but it sorta works. A PTA8 (430C) tip works much better but >I've been burning up a tip every 3 months or so. I just measured the tip temperature with a temperature probe that came with an inexpensive meter I bought a few years ago. The package claims the probe can measure up to 1200 degrees F. so I pressed the heated tip against the probe tip sitting on top of a piece of wood. The tip measured 570 degrees F. max. The thing just seems to be cycling more than I would expect. I'll buy a new tip at Frys tomorrow and see if it works better. I just know that something isn't normal with the station. There's nothing more frustrating than trying to unsolder a component only to have the soldering iron flake out at the worst moment. I solder and repair old tube televisions and radios as well as Pentium 4 motherboards, mostly leaking capacitors and cold solder joints in power supplies. I'm using Kester Kwik-Draw Rosin Core 60% Tin/40% Lead, .053" diameter. What does it mean to burn up a tip? If there's no heating element in these tips how does it burn up? Il mittente di questo messaggio|The sender address of this non corrisponde ad un utente |message is not related to a real reale ma all'indirizzo fittizio|person but to a fake address of an di un sistema anonimizzatore |anonymous system Per maggiori informazioni |For more info https://www.mixmaster.it >The thing just seems to be cycling more than I would >expect. Ok, the thermostat is cycling. I've been assuming that it was NOT cycling. If the temperature is as low as you measure, then the primary temperature determining element is the magnetic in the tip. If it's off for some reason, you will get different temperatures. I've had the base of the tip (the shiny part with the number "7" stamped into it) fall off. I can replace it, but the temperature regulation is rather erratic. >I'll buy a new tip at Frys tomorrow and see if it works better. That will probably solve the problem. You might want to buy a larger blade tip for dealing with physically larger components. >I'm using Kester Kwik-Draw Rosin Core 60% Tin/40% Lead, .053" diameter. I prefer 63/37 but 60/40 is good enough. It should work just fine with the 700F tip. >What does it mean to burn up a tip? If there's no heating element in these >tips how does it burn up? The outer plating disappears. The part that needs to be cleaned and tinned burns up (oxidizes) if left hot and sitting around for 10+ hours per day. Eventually, I can't tin it any more. The solder just doesn't stick. I've tried various potions for re-tinning the tips (Kester Ultrapure Tip Tinner), and Sal Ammonica (a flux), but have had no success in reviving the tips. Only the 800F tips seem to have the problem as the 700F tips last much longer. I would post a photo but I can't find a dead tip. A clue is that the tip slowly turns black instead of the usual shiny (tinned) silver color. SignatureJeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 >>The thing just seems to be cycling more than I would >>expect. [quoted text clipped - 31 lines] > can't find a dead tip. A clue is that the tip slowly turns black > instead of the usual shiny (tinned) silver color. I used to find that my 700 deg tips lasted for months with my Weller PTC on 10-12 hours a day, but recently, I've found them to be burning out in just a few weeks. At first, I thought it might be that the Magnastat was seized shut, overheating the tip, but it is clicking on and off quite normally. Unless Weller have done something to change the tip plating, I can't really think of any other reason that this is occuring. This iron has been the workhorse of my workshop for years, and like the OP on this thread, I am extremely familiar with all aspects of its normal functioning. About the only other possibility that I can think of is that I am doing more lead-free work now than I was, and just maybe, the more aggressive fluxes that are incorporated in this hateful stuff, are attacking the tip plating. I'm actually still not doing anything like as much lead-free soldering as I am leaded, but I guess that after making lead-free joints, solder is still sitting on the tip perhaps for hours at a time. Another slight possibility is that a mix of leaded and lead-free sitting on the tip, is causing problems for the plating. The only reason that I say this, is that when I was researching an article that I wrote on lead-free, I spoke with an expert on the subject, and one of his papers stated quite clearly that leaded and lead-free should not be mixed in the same joint, as it was likely to result in long term compromise of the joint integrity. I'm not sufficiently versed in metalurgy or chemistry to understand why this might be, but maybe a factor ? Arfa >I used to find that my 700 deg tips lasted for months with my Weller PTC on >10-12 hours a day, but recently, I've found them to be burning out in just a >few weeks. I had a similar problem a few years ago. At the time, I had 3 Weller WTCPT irons deployed. Two at my house and one at the office. The one in my shop kept eating tips. They would slowly turn black and refuse to tin. All my tips came from the same batch so it wasn't the tip. I bought about 25 of these stations plus parts at an auction perhaps 20 years ago. I rotated the 3 irons between locations and found that the problem remained with the shop location. Then, I realized that the one thing that I was doing in the shop, but not at the other locations, was using the iron to melt plastic parts. I tended to use it for plastic welding and drilling. I would clean and tin the tip immediately afterwards, but apparently the damage was already done. I'm not sure of the exact mechanism, but something in the plastic might be removing or trashing the plating on the tip. >About the only other possibility that I can think of is that I am doing more >lead-free work now than I was, and just maybe, the more aggressive fluxes >that are incorporated in this hateful stuff, are attacking the tip plating. Most of the rework I do in the office is with the evil lead-free solder. If the board used lead-free, my resoldering should use the same. I have both types of solders and use them as required by the type of board. I haven't seen any such tip problems with lead-free. >I spoke with an expert >on the subject, and one of his papers stated quite clearly that leaded and >lead-free should not be mixed in the same joint, as it was likely to result >in long term compromise of the joint integrity. I'm not sufficiently versed >in metalurgy or chemistry to understand why this might be, but maybe a >factor ? I dunno. I've been told the same thing. That's why I have two rolls of solder at each workstation. I don't really understand the failure mechanism when mixing solder and flux types. However, now that you mention it, I have been replacing tips at a faster rate since I've started using some lead-free solders. I did some Googling for soldering iron tips that were specifically designed for lead-free soldering. I found several, but none that bothered to mention the difference between ordinary and lead-free tips. I'll guess that it's pure marketing and that there's no real difference in construction, other than operating at about 50F higher in temperature. SignatureJeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 > Then, I realized that the >one thing that I was doing in the shop, but not at the other [quoted text clipped - 3 lines] >I'm not sure of the exact mechanism, but something in the plastic >might be removing or trashing the plating on the tip. My guess is that the breakdown of the plastic was releasing a halogen-rich vapor, either from the plastic itself (e.g. PVC is polyvinyl chloride and can release chlorine-rich combustion products) or from a fire retardant (often chlorine- or bromine-based). It would not surprise me if such halogen-rich compounds would be chemically-active enough to corrode the iron plating on a soldering tip, and eventually expose the underlying copper. SignatureDave Platt <dplatt@radagast.org> AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! >> Then, I realized that the >>one thing that I was doing in the shop, but not at the other [quoted text clipped - 12 lines] > chemically-active enough to corrode the iron plating on a soldering > tip, and eventually expose the underlying copper. Which is why they formulate compounds used for conductor to not do that these days. My place of employment uses non halogen compounds and low if no chlorine type chemicals in the plastics used in common cable and wire products. I've seen many times copper wire eroded inside just from its own PVC insulation due to older chemical mixes which we don't use any more. Signaturehttp://webpages.charter.net/jamie_5" >I did some Googling for soldering iron tips that were specifically >designed for lead-free soldering. I found several, but none that >bothered to mention the difference between ordinary and lead-free >tips. I'll guess that it's pure marketing and that there's no real >difference in construction, other than operating at about 50F higher >in temperature. The tips are made of copper, but copper is slightly soluble in tin-lead solder, so the copper is plated with iron, which is much less soluble. To keep the iron from rusting, they do some sort of plating over the iron. Finally the very tip of the tip is tinned with solder. I suspect that one difference between a Rohs tip and a non-Rohs tip would be what solder alloy the tip was tinned with. It's also possible that they use a slightly different alloy in the Curie point sensor to change the temp. set point, but I doubt it. Maybe the thermal contact between the old tip and the new one got so bad that there could be 150 deg difference in the temp between them. Seems unlikely, but I suppose it's possible since the tip is exposed but the sensor is not. I'm glad you found a simple solution. In 30 years of working with these WTCP irons, I've never seen a problem like yours. - ----------------------------------------------- Jim Adney jadney@vwtype3.org Madison, WI 53711 USA ----------------------------------------------- >>I'll buy a new tip at Frys tomorrow and see if it works better. > >That will probably solve the problem. You might want to buy a larger >blade tip for dealing with physically larger components. Just installed and tested a new PTA7 tip and it works fine. The temperature as measured by my probe reads 735 degrees F. The tip was Made in Mexico, July 2007, Lead Free, RoHS compliant. The tip I had been using was 15 years old so maybe it was time for a new one. I also picked up a PTA8 tip but that's still sealed in the bag. Il mittente di questo messaggio|The sender address of this non corrisponde ad un utente |message is not related to a real reale ma all'indirizzo fittizio|person but to a fake address of an di un sistema anonimizzatore |anonymous system Per maggiori informazioni |For more info https://www.mixmaster.it > On Sun, 24 Aug 2008 07:25:14 +0200 (CEST), George Orwell > >What does it mean to burn up a tip? > The outer plating disappears. The part that needs to be cleaned and > tinned burns up (oxidizes) if left hot and sitting around for 10+ > hours per day. Eventually, I can't tin it any more. The tips are copper, with an iron-alloy slug for temperature control, and iron/silver plated. To re-tin after the silver is gone, use silver solder (90% Ag kind of silver solder... jewelry craft suppliers will sell by the ounce). It takes at least a hot propane torch, MAPP or air/acetylene is better, to get to temperature for this kind of operation. > What does it mean to burn up a tip? If there's no heating element in these > tips how does it burn up? I assume he means the plating gets destroyed so it doesn't tin properly anymore. I have a pile like that. :( :) -- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/ Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/ +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs. >I have a Weller WTCPT soldering station with the stock TC201T handle and >PTA7 700 degrees F. tip. It's 15 years old and hasn't seen much action. I [quoted text clipped - 6 lines] >heated tip against the sponge, I barely get much of a sizzle. Solder barely >melts but does melt, just barely though. These are great stations, but many of them have one common flaw: One of the crimped female pins in the base, where you plug in the iron, is often crimped onto solid wire, and that connection will go bad within about a year of reasonable use. Once that connection goes bad, it will heat up and destroy the plastic connector body, so the best thing to do is to fix it before it gives problems. When we used to buy these new, I would fix this in new units before they were ever turned on. If you have a large selection of pin remover tools you may have one that will work on these, but I've often had to make do with a bit of rolled up soda can alum sheet. It's tedious, but you really only HAVE to remove the one solid wire. The stranded crimps will be fine. Once you get the pin out, just solder it and put it back. My guess is that this is what's happened to your station. The power is being split between the heater and the connector. It's also possible that the switch in the iron handle is going bad. That certainly happens, but usually only after a lot of use. The Magnestat control depends on the Curie temp of the alloy in the little slug at the end of the tip. That will never change. It's a little confusing that you say you can hear the Magnestat control switching back and forth. This is normal, but it should only happen if the tip is reaching it's 700 F Curie temp. This one observaion makes me wonder if you're just not remembering how it used to work. Even if it doesn't happen to be the problem right now, it's still a good idea to solder that pin, because it will save you headaches down the road. - ----------------------------------------------- Jim Adney jadney@vwtype3.org Madison, WI 53711 USA ----------------------------------------------- > I have a Weller WTCPT soldering station with the stock TC201T handle and > PTA7 700 degrees F. tip. It's 15 years old and hasn't seen much action. I [quoted text clipped - 17 lines] > lose their temperature calibration? Is it time for a new soldering > station? Any opinions on the WESD51? You say you "can hear the tip cycling". If that's the case, it would seem that there can't be anything wrong with the electrical parts. The tip cycles based on reaching the curie temperature of the magnet. Have you tried a new tip? -- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/ Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/ +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs. Does this unit have a temperature-calibration pot? >Does this unit have a temperature-calibration pot? No. The Weller WTCPT has no controls or adjustments. The primary temperature determining component is the curie point of the magnet in the tip. At low temperatures, the magnet holds a piston, which pulls a pair of relay type contacts closed, which then runs the heating element. When the tip temperature reaches the curie point, the magnetism disappears, opening the contacts. There's nothing in the contact assembly that would affect the temperature, except perhaps if the piston were stuck. That's unlikely because of the huge clearances involved. If it's cycling, then only the tip can affect the temperature threshold. Weller manuals: <http://bama.sbc.edu/weller.htm> WTCPT manual: <ftp://bama.sbc.edu/downloads/weller/wtcpt/> (215KB) See section on "Principle of Operation". SignatureJeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 > > I have a Weller WTCPT soldering station with the stock TC201T handle and > > PTA7 700 degrees F. tip. It's 15 years old and hasn't seen much action. I [quoted text clipped - 23 lines] > > Have you tried a new tip? Well there is the issue of lead-free solder too which requires a 50C (90F) or so hotter tip. Graham > I have a Weller WTCPT soldering station with the stock TC201T handle and > PTA7 700 degrees F. tip. It's 15 years old and hasn't seen much action. I [quoted text clipped - 24 lines] > Per maggiori informazioni |For more info > https://www.mixmaster.it Remember to replace the shroud that screws on and retains the tip, it is part of the magnetic "circuit" and if absent causes that sort of problem. Also if you're careful , ie parallel jaw pliers, you can pull off the magnastat of a worn tip and change the temp on another good but wrong temp tip. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ >Remember to replace the shroud that screws on and retains the tip, it is >part of the magnetic "circuit" and if absent causes that sort of problem. No, it's not part of the magnetic circuit. The magnestat works just fine without the sleeve. The only problem is that without the sleeve, when the tip becomes non-magnetic at the Curie temp it falls out of the iron. >Also if you're careful , ie parallel jaw pliers, you can pull off the >magnastat of a worn tip and change the temp on another good but wrong temp >tip. Now THAT's a useful tip! Thanks. - ----------------------------------------------- Jim Adney jadney@vwtype3.org Madison, WI 53711 USA ----------------------------------------------- > >Remember to replace the shroud that screws on and retains the tip, it is > >part of the magnetic "circuit" and if absent causes that sort of problem. [quoted text clipped - 15 lines] > Madison, WI 53711 USA > ----------------------------------------------- It is easy , on checking different tips rather than soldering, to not replace the cover. Whether it is a magnetic effect or a positioning effect, I don't kniow, but it can affect the switching action. Another tip ;-) Fit a TO220 transistor insulator/ washer above and below each of the 3 screw-heads that hold the end plate to the plastic handle - stops excess heat cracking the plastic at the screws. I must be doing something right , my one is at least 22 years of daily use with the same heater, switch, cord etc, I've only changed bits. I only switch on prior to use , not left on all the time. Gives a time to reflect - is the kit powered up? , have I confused left and right on turning the board over? etc. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ >> >Remember to replace the shroud that screws on and retains the tip, it is >> >part of the magnetic "circuit" and if absent causes that sort of problem. [quoted text clipped - 3 lines] >> when the tip becomes non-magnetic at the Curie temp it falls out of >> the iron. >It is easy , on checking different tips rather than soldering, to not >replace the cover. Whether it is a magnetic effect or a positioning effect, >I don't kniow, but it can affect the switching action. I just did the most fundamental test on the sleeve. It's not ferromagnetic at all. Therefore I don't see how it can have any effect on the magnetic field at all. What kind of effect do you think you've seen. >Another tip ;-) >Fit a TO220 transistor insulator/ washer above and below each of the 3 >screw-heads that hold the end plate to the plastic handle - stops excess >heat cracking the plastic at the screws. Sounds reasonable, except that I've never seen heat damage to the screw anchor points in the plastic. I've certainly seen damage due to careless starting of the screws without regard to not starting in the original thread. I'm surprised that those washers tolerate that heat. I'd expect it to be a lot hotter there than the application they were designed for. >I must be doing something right , my one is at least 22 years of daily use >with the same heater, switch, cord etc, I've only changed bits. I only >switch on >prior to use , not left on all the time. Gives a time to reflect - is the >kit powered up? , have I confused left and right on turning the board over? >etc. Mine's 31 years old. Not used all that often, but left on once I'm on a job. I like these because you CAN leave them on without much harm. My original heater burned out last year. Other than fixing the base station outlet wiring when it was new, that was the only repair it's needed. I think I'm on my second tip. I retin them by stirring them around in that brown greasy soldering flux. - ----------------------------------------------- Jim Adney jadney@vwtype3.org Madison, WI 53711 USA ----------------------------------------------- > I have a Weller WTCPT soldering station with the stock TC201T handle and > PTA7 700 degrees F. tip. I prefer 800 degrees. Always have done. Esp with small tips. The idea is to get the soldering done as fast as quickly, not leave the joint cooking until the solder finally melts. I've seen plenty of 'cold' / 'dry' joints arising from the use of 700F tips. I even told the manufacturing dept of a certain company to change to 800F tips for a certain process but they moaned that 'the tips wear out faster'. So the returns rate went up again Bloody idiots. Graham >I prefer 800 degrees. Always have done. Esp with small tips. The idea is to get >the soldering done as fast as quickly, not leave the joint cooking until the >solder finally melts. I have to disagree. 700 F is already way above the melting point of the solder. If you need more heat you might want to use a larger tip, with greater thermal mass, but higher temps are much more likely to damage the board. >I've seen plenty of 'cold' / 'dry' joints arising from the use of 700F tips. I >even told the manufacturing dept of a certain company to change to 800F tips >for a certain process but they moaned that 'the tips wear out faster'. So the >returns rate went up again Bloody idiots. Good soldering technique will not give cold solder joints, regardless of the tip temp. High tip temp is probably a poor way to overcome poor technique. Using a higher temp iron will certainly pump more heat into the joint in a given time, but it also results in more temp difference across the joint, so you may be more likely to get what looks like a good joint on the heated side, but with little penetration. We've been using Rohs solder for quite a few years now, and I don't have a bit of trouble with it using a 700 F tip. - ----------------------------------------------- Jim Adney jadney@vwtype3.org Madison, WI 53711 USA ----------------------------------------------- >>I prefer 800 degrees. Always have done. Esp with small tips. The idea is >>to get [quoted text clipped - 18 lines] > of the tip temp. High tip temp is probably a poor way to overcome poor > technique. I would absolutely dispute that statement > Using a higher temp iron will certainly pump more heat into > the joint in a given time, but it also results in more temp difference > across the joint, so you may be more likely to get what looks like a > good joint on the heated side, but with little penetration. ?? > We've been using Rohs solder for quite a few years now, and I don't > have a bit of trouble with it using a 700 F tip. I would suggest Jim, that it does rather depend on what exactly you are soldering. If you are making consistently good lead-free joints with a 700 deg Weller tip in all circumstances, then you are doing a lot better than most of the major manufacturers. Since they started using the stuff, the service industry has seen a huge leap in bad joints - and not always in 'traditional' places where you might expect to find them. Whilst you are correct in that a 700 deg tip melts lead-free solder, it does not do so anything like as well as it does with leaded solder. Although lead-free solder does not have as nice a melt / flow characteristic as leaded in the first place, this undesirable quality is made much worse by not having enough temperature on it - particularly when soldering a component with a high thermal inertia, such as a connector or power semiconductor. The fact that lead-free solder is much worse at wetting most of the metals commonly used in electronic circuit construction, further exacerbates the problem, and dictates that more aggressive fluxes are used in the hateful stuff. Unless these are given the opportunity to do their work, by allowing them to reach the temperatures they need to at the soldering surface, then the likely result will be a bad joint - and one that's invisible to the naked eye, and may not give trouble for some time, at that. Many bad joints in lead-free that I come across in daily work, show no signs of external distress at all (except that *all* lead-free joints look distressed), and do not respond to tapping, freezing or heating. The only conclusion has to be that whilst the solder has stuck ok to the copper pad, it hasn't to the component leg inside the joint. Probably, a classic example of the 'cold' joint that engineers your side of the pond, are fond of calling them. Use of a bigger tip to improve its own thermal inertia, is not an option these days for general electronic service work. A finely pointed conical or small screwdriver tip, is the order of the day. Component pin densities, and component placement densities, are such that only a small tip and fine gauge solder are appropriate in most cases, and it's just not a practical proposition to keep changing tips, depending on what exactly is on your bench at the time. When Weller came up with the 700 deg tip, it was with a traditional tin lead solder alloy in mind. It is the tip that has always been supplied with these irons from new. Lead-free melts at a temperature of 30 to 50 deg F higher than leaded, so based on Weller's determination of 700 deg being appropriate for leaded solder, you would have to extrapolate this thinking to come up with a tip temperature of perhaps 750 deg, which is what I have both my variable temperature controlled station, and vacuum desoldering stations set to, for lead-free work. So I'm with Graham on this one (who is, like me, experienced in daily soldering over many many years) in that for lots of lead-free work with a Weller Magnastat iron, the best combination is a small tip, but with a lot of heat behind it in the form of it being an 800 deg rated one. I don't dispute that you can make good joints in lead-free with a 700 deg tip, as I do it myself, but it does require very considerable care and experience to 'do it right'. There are now more appropriate soldering tools on the market for lead-free work, than the good old TCP irons. There are some interesting notes here about why the 'standard' tips burn out quickly, when used with lead-free http://www.cooperhandtools.com/europe/sales_literature/documents/Leadfree_Info_GB.pdf Arfa >> Good soldering technique will not give cold solder joints, >> regardless of the tip temp. High tip temp is probably >> a poor way to overcome poor technique. > I would absolutely dispute that statement. As would I. The temperature has to be at least high enough to bring the solder to its "liquidus" state. (Which is one of the reasons eutectic solder is preferable.) >> Using a higher temp iron will certainly pump more heat into the >> joint in a given time, but it also results in more temp difference >> across the joint, so you may be more likely to get what looks >> like a good joint on the heated side, but with little penetration. This is bilge. >>> Good soldering technique will not give cold solder joints, >>> regardless of the tip temp. High tip temp is probably [quoted text clipped - 5 lines] >solder to its "liquidus" state. (Which is one of the reasons eutectic solder >is preferable.) I certainly agree that we have to work above the liquidus. You're also quite right about the advantage of working with a eutectic. 700 F is still quite a bit above the liquidus. Before you get in too deep arguing for higher temps. you might want to check out the reference that Arfa so kindly provided. http://www.cooperhandtools.com/europe/sales_literature/documents/Leadfree_Info_GB.pdf >>> Using a higher temp iron will certainly pump more heat into the >>> joint in a given time, but it also results in more temp difference >>> across the joint, so you may be more likely to get what looks >>> like a good joint on the heated side, but with little penetration. > >This is bilge. It's clear that you disagree, but is it possible that you don't understand the problem? - ----------------------------------------------- Jim Adney jadney@vwtype3.org Madison, WI 53711 USA ----------------------------------------------- > 700 F is still quite a bit above the liquidus. And how long do you think it's actually going to take the SOLDER to reach that temp ? Ever heard of thermal inertia ? Graham >Ever heard of thermal inertia ? If you actually mean specific heat, yes. - ----------------------------------------------- Jim Adney jadney@vwtype3.org Madison, WI 53711 USA ----------------------------------------------- > >Ever heard of thermal inertia ? > > If you actually mean specific heat, yes. And what you mean is 'heat capacity' which is NOT the same thing ! Although it's value depends on specific heat too. " Heat capacity (symbol: Cp) as distinct from specific heat capacity is the measure of the heat energy required to increase the temperature of an object by a certain temperature interval. " http://en.wikipedia.org/wiki/Heat_capacity Graham > >> Good soldering technique will not give cold solder joints, > >> regardless of the tip temp. High tip temp is probably [quoted text clipped - 12 lines] > > This is bilge. Quite. The total stress on the components is in fact likely to be be LESS. Graham >> >> Good soldering technique will not give cold solder joints, >> >> regardless of the tip temp. High tip temp is probably [quoted text clipped - 14 lines] > >Quite. The total stress on the components is in fact likely to be be LESS. Before you guys all continue to pile on, you might want to actually read the link that Arfa posted. They are quite emphatic about avoiding the proceedure you're all supporting. Read it. It's informative. - ----------------------------------------------- Jim Adney jadney@vwtype3.org Madison, WI 53711 USA ----------------------------------------------- > >> >> Good soldering technique will not give cold solder joints, > >> >> regardless of the tip temp. High tip temp is probably [quoted text clipped - 18 lines] > read the link that Arfa posted. They are quite emphatic about avoiding > the proceedure you're all supporting. Read it. It's informative. My experience says otherwise. I'll have to time how long it takes to solder say a 1/4W resistor but it's certainly less than the 3 seconds or so some have mentioned with 700F tips. Plus note my post about those cold joints that plagued an amp design that just 'went away' with 800F tips. Graham [snip...snip...] >There are some interesting notes here about why the 'standard' tips burn out >quickly, when used with lead-free > >http://www.cooperhandtools.com/europe/sales_literature/documents/Leadfree_Info_GB.pdf Interesting phrase there: "Clean the tip on a watery swamp." That one required a quick mental recalibration... On that issue, though, what are your thoughts on the use of brass turnings as a tip cleaner vice a dunk in the swamp? I switched over to the bowl of brass a while ago and now prefer it to the damp sponge. SignatureRich Webb Norfolk, VA >[snip...snip...] >>There are some interesting notes here about why the 'standard' tips burn out [quoted text clipped - 4 lines] >Interesting phrase there: "Clean the tip on a watery swamp." That one >required a quick mental recalibration... Yes, that was quite confusing for a few moments. >On that issue, though, what are your thoughts on the use of brass >turnings as a tip cleaner vice a dunk in the swamp? I switched over to >the bowl of brass a while ago and now prefer it to the damp sponge. I've never used one of those, but I've wondered how they would be. I'd be concerned that they would wear thru the tip plating quickly and lead to early death of the tips. Have you noticed any of that? - ----------------------------------------------- Jim Adney jadney@vwtype3.org Madison, WI 53711 USA ----------------------------------------------- >>[snip...snip...] >>>There are some interesting notes here about why the 'standard' tips burn out [quoted text clipped - 14 lines] >be concerned that they would wear thru the tip plating quickly and >lead to early death of the tips. Have you noticed any of that? None at all. I'm love to see a comparative study, though; must be one out there somewhere in the vast Intertoobz. I've been pleased with it. No more hiss'n'sizzle. SignatureRich Webb Norfolk, VA >I've never used one of those, but I've wondered how they would be. I'd >be concerned that they would wear thru the tip plating quickly and >lead to early death of the tips. Have you noticed any of that? > >- I also use one of those, and if anything, my tips last longer. Andy Cuffe acuffe@gmail.com > [snip...snip...] > >There are some interesting notes here about why the 'standard' tips burn out [quoted text clipped - 8 lines] > turnings as a tip cleaner vice a dunk in the swamp? I switched over to > the bowl of brass a while ago and now prefer it to the damp sponge. I tried one of those brass things and it was useless IMHO. It left loads of crap on the tip. Use a moist Weller sponge every time. Graham >> On that issue, though, what are your thoughts on the use of brass >> turnings as a tip cleaner vice a dunk in the swamp? I switched over to [quoted text clipped - 4 lines] > > Graham I switched to using "Stainless Steel" Pot scrubbers nearly 40 years ago, NOT "Steel wool" It's stuffed into the bottom of the soldering iron Holder, just a twist inserting or removing the Iron is usually enough to keep the tip clean. To clear a really dirty tip, a few swipes on the outside of the holder is sufficient. Do not use "Steel Wool"! it will dissolve in the hot solder to form all sorts of crud and scraps will stick to the magnetic tips. Yukio YANO >>> I prefer 800 degrees. Always have done. Esp with small tips. The idea is >>> to get [quoted text clipped - 89 lines] > > Arfa Thanks, Arfa for the dissertation on RoHs solder. I'm lucky enough to have had no dealings with the nasty stuff as most (as in 95%+) of the repairs in newer stuff I work on is boardswap or exchange. I know I'll eventually have to mess with it and miss the old leaded stuff I've been doing since 1959... I'll have to look up what Pace is doing for RoHs soldering and desoldering tips. At least I know my own home WTCPT unit will cope with RoHs solder in a fashion. >>>> I prefer 800 degrees. Always have done. Esp with small tips. The idea is >>>> to get [quoted text clipped - 102 lines] >At least I know my own home WTCPT unit will cope with RoHs solder in a >fashion. This EU RoHs requirement for lead free solder is the precise reason the XBOX 360 has had such a high failure rate. > >I'll have to look up what Pace is doing for RoHs soldering and > >desoldering tips. [quoted text clipped - 4 lines] > This EU RoHs requirement for lead free solder is the precise reason the XBOX > 360 has had such a high failure rate. I hate to think what's lurking in the woodwork. At least aerospace is exempt ! I don't know about car ECUs though. That could be fun. Lead-free hates vibration with a vengeance. As I may have said elsewhere I know that at least one loudspeaker manufacturer got an exemption because the sound was causing lead-free lead-out wire terminations to fail. There's implications there for a lot of sound equipment. Graham >>>I prefer 800 degrees. Always have done. Esp with small tips. The idea is >>>to get [quoted text clipped - 35 lines] >deg Weller tip in all circumstances, then you are doing a lot better than >most of the major manufacturers. Not sure what you're basing this on, since I doubt that any major manufacturer is using irons in production. I would expect any real production to be wave soldered for the last 20 years. I'm sure, however, that wave soldering, with which I have no experience, has its own set of problems. >Whilst you are correct in that a 700 deg tip melts lead-free solder, it does >not do so anything like as well as it does with leaded solder. Although >lead-free solder does not have as nice a melt / flow characteristic as >leaded in the first place, this undesirable quality is made much worse by >not having enough temperature on it My own experience doesn't support your claims. I wish I could tell you exactly what alloy we have at work, but it melts and flows perfectly well. That could certainly be due to the flux, but I've noticed no adverse effects from the flux. You also seem to be confusing the concepts of heat and temperature, and the distinction between the two is important. One thing that DOES bother me about the lead free solders is that everyone suggests that it is important to do repairs with the same alloy as originally used. However there seem to be several lead free alloys, and it does not seem that one can tell the difference between them visually. So how does one know what to do when presented with a lead free board to repair? >Use of a bigger tip to improve its own thermal inertia, is not an option >these days for general electronic service work. A finely pointed conical or [quoted text clipped - 3 lines] >proposition to keep changing tips, depending on what exactly is on your >bench at the time. I agree that you can't be expected to use a large blunt tip on a fine pitch high density board, but the link you provided below points out other ways to accomplish the same thing. >When Weller came up with the 700 deg tip, it was with a traditional tin lead >solder alloy in mind. It is the tip that has always been supplied with these [quoted text clipped - 4 lines] >variable temperature controlled station, and vacuum desoldering stations set >to, for lead-free work. This assumes that the 700 F was chosen because it was perfect for tin/lead solder. There were probably other considerations, too, like heat content and the typical thermal mass of electrical connections when these irons first came out. Since many of those connections were still point-to-point they would have needed much more heat than present day junctions. >So I'm with Graham on this one (who is, like me, experienced in daily >soldering over many many years) in that for lots of lead-free work with a [quoted text clipped - 4 lines] >'do it right'. There are now more appropriate soldering tools on the market >for lead-free work, than the good old TCP irons. It's certainly clear that we're each entitled to our opinions. >There are some interesting notes here about why the 'standard' tips burn out >quickly, when used with lead-free > >http://www.cooperhandtools.com/europe/sales_literature/documents/Leadfree_Info_GB.pdf That's an interesting link that I haven't seen before and I appreciate your pointing it out. I can't help mentioning that one thing it says is that one should be very careful to avoid the temptation to increase the soldering temperature when using lead free solder. The first thing I actually noticed about this pdf was that it seemed to be extremely poorly written. As Cooper Tools is a US company, I thought it unusual that their English would be so poor. I'm even more surprised to see that this comes from Cooper Tools GMBH (Germany.) In spite of the poor translation, I suspect that they have much more experience with the lead free problem than we do, and the meaning of their writing is still, in most cases, clear. - ----------------------------------------------- Jim Adney jadney@vwtype3.org Madison, WI 53711 USA ----------------------------------------------- Don't know about different types of lead-free solder. But distinguishing lead free I've found is 1/ conical rather than domed solder joints 2/ putting a stainless steel sewing needle in some of the solder after melting and extracting needle while still molten, it is much more difficult to remove the cold solder from the needle than doing the same with leaded solder. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ > Don't know about different types of lead-free solder. > But distinguishing lead free I've found is [quoted text clipped - 9 lines] > electronic hints and repair briefs , schematics/manuals list on > http://home.graffiti.net/diverse:graffiti.net/ And many boards now actually state that they are lead free or "PbF" on the silk screening. As far as I have been able to tell, it's not so much about mixing different types of lead-free alloys, which may or may not contain small traces of other metals such as silver, but more a case of not mixing lead-free with leaded solder. To Jim. All of my experience with this stuff is from a service rather than production point of view. You are of course right that manufacturers use wave or reflow soldering, and have done for many years. The point I was making about lead-free joints and Weller TCPs at 700 deg, versus manufacturers' joints, was perhaps not grammatically well-made. What I was basically saying was that the manufacturers, with all of their expertise and expensive production soldering equipment, still can't get to grips with the stuff themselves, and are still producing equipment littered with bad joints from day one. So, if you are making consistently good 'production' joints in lead free, using 700 degree hand soldering equipment designed way way before any eco-prat had ever come up with the concept of taking the lead out of solder, then you (your company) are doing, on average, better than the big boys. As far as heat and temperature are concerned, I take your point that they are not the same thing, and I don't think that I am confusing the two. They are however, inextricably linked to one another by external influences. Energy, in the form of heat, is what has to be put into a body in order to raise its temperature. All solder has to have its temperature raised to the point where its liquid state becomes suitable for making a soldered joint, and then maintained at that temperature until the joint is completed. The temperature at which this condition occurs for lead-free solder, is higher than that of leaded solder. If you are just making small joints, then this is of no consequence, and a 700 degree tip is fine for the job. With a leaded joint - even a large one that causes the tip temperature to drop by a few degrees - that drop is again of little consequence, as there is plenty of temperature 'overhead' available from a 700 deg tip. However, with lead-free, 50 degrees of that overhead, have already gone, so if a joint is any bigger than 'small', the additional temperature drop at the tip, caused by the joint leaching heat from it, results in a less than adequate tip temperature being maintained, to correctly complete the joint. The result is a bad or 'cold' joint. A 700 degree tip simply cannot maintain enough heatflow into the solder, to keep it at a sufficient temperature to do a 'good job' on anything other than a small joint, and this is particularly the case where a 'typical' repair workshop tip of small dimensions is used. I have a repair service for a particular board which uses lead-free, and I see many of them where the shop that's sending it back to me, have attempted some rework or component replacement, and it's quite obvious that they have been trying to use their normal leaded soldering equipment to do the job, with the inevitable consequences. I can accept what Cooper say about not being tempted to increase the tip temperature, but I think that they are probably talking more about not going up far enough to get the same 'feel' with lead-free, as with leaded. Most commentators on the subject, including soldering equipment manufacturers, agree that a higher nominal tip temperature is required to work reliably with lead-free. One of the main reasons that manufacturers are having so much trouble with the stuff, is that they have to run their soldering processes at a higher temperature. This then brings them close to the maximums that some of the components can tolerate for any length of time, so they have to compromise and run the process at a slightly reduced temperature. That is fine until you have to solder a connector or power semiconductor - particularly one that is mounted on a heatsink, and that is where many lead-free bad joints are occuring. Trust me, if manufacturers didn't *have* to run their processes at a higher temperature, with all of the implications of that, including a higher energy useage, to cope with lead-free, then they wouldn't ... Arfa > > Don't know about different types of lead-free solder. > > But distinguishing lead free I've found is [quoted text clipped - 78 lines] > > Arfa Is all your info available collated together on a website somewhere. ? Any comments on the following If replacing new (ROHS) components to old boards (leaded solder) then scrape off most of the hard mirror-like finnish on the leads before tining with and then soldering with Pb-Sn solder 21Century RoHS boards , repair of but not production (heavy solder usage), use silver solder, or is that likely to lead to as much a problem as mixing RoHs and PbSn solder. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ > Arfa Daily wrote in message > [quoted text clipped - 20 lines] > use silver solder, or is that likely to lead to as much a problem as mixing > RoHs and PbSn solder. I read somewhere a while back that the military, aerospace and telecoms guys were sending components out to de 'de-tinned' of lead free and re-tinned with the proper stuff. Crazy ! Otherwise you can get problems. Graham > > Arfa Daily wrote in message > > [quoted text clipped - 28 lines] > > Graham When you see brand new components with that hard shiny neat? tin finnish its hardly surprising there is tin pest problems before anything to do with microcracking in the solder. Not surprising that such components, after a few months, can be pulled out by hand leaving neat square holes . It would take a blow torch almost, to meld with that tin finnish, when on thick say TOP3 leads. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ >> > Don't know about different types of lead-free solder. >> > But distinguishing lead free I've found is [quoted text clipped - 130 lines] > electronic hints and repair briefs , schematics/manuals list on > http://home.graffiti.net/diverse:graffiti.net/ I don't have info particularly collated anywhere, but if you want to contact me off group with an address that's monitored for input, I'll send you a copy of the article, which contains references to where I got info, and who from. I don't think that there is any particular need to remove the surface of RoHS compliant components' leads. I seem to recall reading somewhere that most component leads are now tin plated, as in coated in neat tin, rather than being 'tinned' with any kind of solder, as they were in the past. A coating of pure tin should not cause any problems when used with a conventional SnPb solder. As far as using silver solder is concerned, I don't believe that there is any need to go to those lengths. Given the limited life and price of modern equipment, I think that any repair that keeps a piece of kit going for another year is a result, and if the joint that you made as part of the repair gives up after that time, then san fairy ann ... Some commentators suggest using a lead-free alloy which contains a small quantity of silver for hand work. These alloys have a melting point closer to that of SnPb solder, and similar 'workability', but do of course, cost significantly more, so I don't bother with them, for the same basic reasons of equipment life / value. On that score, just out of interest, I bought a little DVD player from the local Tesco store last week. It's about the size of a portable player, but without the LCD screen. It plays every format imaginable, gives a cracking picture on my (CRT !) TV, and came with all leads and a very comprehensive user guide in good english. It even has a full function 'credit card' remote control. How much ? Fifteen quid !! ($27). If it goes wrong, it's just toss-away. Don't care what solder it's made with ... Arfa > I don't have info particularly collated anywhere, but if you want to contact > me off group with an address that's monitored for input, I'll send you a [quoted text clipped - 5 lines] > coating of pure tin should not cause any problems when used with a > conventional SnPb solder. The military etc are still worried because of potential tin whiskers with closely spaced device leads. There are known examples of such inter-lead shorts and they can support up to 30mA I read somewhere IIRC. I had a fantastic picture of one once. It shorted out a *crystal*. Graham >> I don't have info particularly collated anywhere, but if you want to >> contact [quoted text clipped - 20 lines] > > Graham Been some interesting stuff recently in Elektor mag on the subject, and how the old AF117's used to fail in SO mixers used in early tranny radios. Seems that was due to whiskers growing inside the metal can of the transistor, which was tin plated, and shorting to the transistor itself. Many engineers just used to snip the screen lead on the transistor, but I found that if you quickly jabbed a screwdriver across between the screen and collector leads, the short magically disappeared. I guess it was blasting off the microscopic whisker by vapourising it. Arfa > "Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message > > [quoted text clipped - 13 lines] > the short magically disappeared. I guess it was blasting off the microscopic > whisker by vapourising it. Now how did you devise that technique ? Graham >> "Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message >> > [quoted text clipped - 26 lines] > > Graham Christ knows Graham ! I was about 18 at the time and probably about the only one in the workshop who was reasonably comfortable with the new fangled transistors ... Thinking about it, the leads went E-B-Scr-space-C. It was probably one of those fortuitous 'mistakes' where I was measuring the collector voltage, and the meter probe slipped ... Arfa > > Arfa Daily wrote: > >> [quoted text clipped - 18 lines] > those fortuitous 'mistakes' where I was measuring the collector voltage, and > the meter probe slipped ... Unlike me designing power amps where a similar slip tends to result in a lot of magic smoke being let out. Graham >> > Arfa Daily wrote: >> >> [quoted text clipped - 31 lines] > > Graham Oh I had to work on them too ! Our company was responsible for background music machines that were rented out ro shops etc. They used a sort of cassette tape that was endless (!) in that it wound off the centre and back on to the outside. Bit like an 8 track mechanism, but only had four tracks, as I recall. Anyways, they had a bloody great amplifier built into them, based on 2N3055s. Being an early design, there was no protection or bias stabilization, and you only had to bring a 20k / volt meter near to some points to get them to run away, releasing their magic smoke ... Happy days. It's back when engineers learnt the business properly d:~} Arfa > Oh I had to work on them too ! Our company was responsible for background > music machines that were rented out ro shops etc. They used a sort of [quoted text clipped - 5 lines] > points to get them to run away, releasing their magic smoke ... Happy days. > It's back when engineers learnt the business properly d:~} That sounds a lot like the Viking/Telex decks that used a Fidelipac/NAB Broadcast cartridge. They sold the bare decks, with or without the heads and sensors, and the customer built their own electronics. I think I still have the Sam's on the bare deck, somewhere. http://en.wikipedia.org/wiki/Fidelipac <http://images.google.com/images?hl=en&rls=com.microsoft:en-us:IE-SearchBox&rlz=1 I7GGLD&resnum=0&q=Fidelipac&um=1&ie=UTF-8&sa=N&tab=wi> The 3M background music system used a bigger cartridge, with a pair of stacked, 7" Reels. It was four track as weel. it played to one end, revesed direction to play track two. When that ran out, it reveresd again, and selectd the third track... When it finished the fourh track, it started over. It ran at a very low speed and had something like eight hours of music. Signaturehttp://improve-usenet.org/index.html aioe.org, Goggle Groups, and Web TV users must request to be white listed, or I will not see your messages. If you have broadband, your ISP may have a NNTP news server included in your account: http://www.usenettools.net/ISP.htm There are two kinds of people on this earth: The crazy, and the insane. The first sign of insanity is denying that you're crazy. > "Eeyore" wrote in message > >> [quoted text clipped - 14 lines] > points to get them to run away, releasing their magic smoke ... Happy days. > It's back when engineers learnt the business properly d:~} An, the days of 50uA meter movements. I do still have a small one and even found a leather BT case designed for it on the local market. Graham >> "Eeyore" wrote in message >> >> [quoted text clipped - 26 lines] > > Graham My good old AVO 8 Mk IV, which was originally issued to me as an apprentice in about 1970, is still used every day. For 'resistance path' fault finding, and semiconductor junction basic proving, it is still my instrument of choice. There's something very comforting about seeing a needle swing over to 'about the right place'. I do of course have a raft of digital multimeters, both portable and bench, and a full array of digital capacitance and ESR and so on meters for more precise measurements where needed, but I find that a good quality analogue meter still fits the bill for much general service work. Arfa > > Arfa Daily wrote: > >> > Arfa Daily wrote: [quoted text clipped - 26 lines] > choice. There's something very comforting about seeing a needle swing over > to 'about the right place'. And it's horrid seeing the movement protection fail ! > I do of course have a raft of digital multimeters, both portable and bench, > and a full array of digital capacitance and ESR and so on meters for more > precise measurements where needed, but I find that a good quality analogue > meter still fits the bill for much general service work. I only really use it where the mechanical averaging is useful, such as noise measurements. Otherwise it's my trusty Fluke 77. I think I've only ever seen one 'go wrong' and it was repaired or replaced under warranty even though we didn't have the invoice because they track the serial numbers themselves. Graham > Oh I had to work on them too ! Our company was responsible for > background music machines that were rented out ro shops etc. They [quoted text clipped - 8 lines] > > Arfa Hmmm...I used to be an apprentice at a company that manufactured background music machines utilising those big cartridges. They sounded bloody awful with violin music on - used to warble something chronic. For test purposes us young lads recorded stuff like Jimi Hendrix on them! Roy >> Oh I had to work on them too ! Our company was responsible for background >> music machines that were rented out ro shops etc. They used a sort of [quoted text clipped - 14 lines] > > Roy Sounds like we might be from the same background. Training school at Poulton-le-Fylde near Blackpool, by any chance ? Arfa >>> Oh I had to work on them too ! Our company was responsible for >>> background music machines that were rented out ro shops etc. They [quoted text clipped - 21 lines] > > Arfa Close - Ditchburns at Lytham, then Granada TV at Layton. Roy >>>> Oh I had to work on them too ! Our company was responsible for >>>> background music machines that were rented out ro shops etc. They used [quoted text clipped - 23 lines] > > Roy Ah, right. I was one of the 'Redi Boys' that's Rediffusion. Eventually, Granada took us over, but I was long gone by then. Arfa >> I don't have info particularly collated anywhere, but if you want to contact >> me off group with an address that's monitored for input, I'll send you a [quoted text clipped - 14 lines] > > Graham The same thing happened with early-manufactured 72 'pin' SIMMs that had tin contacts (typically the cheap generic RAM sitcks). 30 'pin' tin contact SIMMs were 'coarse pitch' enough that the problem occurred rarely. I also saw the same issue on some UK-manufactured electric traffic counters (those boxes with the hoses laid across the pavement). They left the thru-leads so long that the tin coating on on the leads protruding out of the hole would grow whiskers. We had no schematics and the chips were all marked only with proprietary numbers, all we could do to fix them locally was to check discrete components on guesstimate as to what their function was, and do an extremely close scrutiny on the boards. We found those whiskers on quite a few of them, so it became a shop standard to trim all the leads on the boards and scrub them before giving up and RMAing the units. That cured probably 70% of the problems. > >> I don't have info particularly collated anywhere, but if you want to contact > >> me off group with an address that's monitored for input, I'll send you a [quoted text clipped - 27 lines] > shop standard to trim all the leads on the boards and scrub them before > giving up and RMAing the units. That cured probably 70% of the problems. Pathetic. Bloody alleged 'greens' and gullible politicians.. Combine the two and you have a disaster. Graham >> Is all your info available collated together on a website somewhere. ? >> [quoted text clipped - 20 lines] > you a copy of the article, which contains references to where I got info, > and who from. On its way. Check your incoming. Let me know if any probs. Arfa >>> Is all your info available collated together on a website somewhere. ? >>> [quoted text clipped - 24 lines] > > Arfa Sent again using the first 'reserve' address. Let me know ... Arfa > >>> Is all your info available collated together on a website somewhere. ? > >>> [quoted text clipped - 28 lines] > > Arfa All received, not had a chance to read it yet > >> > Don't know about different types of lead-free solder. > >> > But distinguishing lead free I've found is [quoted text clipped - 5 lines] > > leaded > >> > solder. > I don't have info particularly collated anywhere, but if you want to contact > me off group with an address that's monitored for input, I'll send you a [quoted text clipped - 14 lines] > cost significantly more, so I don't bother with them, for the same basic > reasons of equipment life / value. My experiences of RoHS, so far For post 2006 repair work I use (lead-free) silver solder , despite it leaving a grey "bad" looking joint. For an average repair, for me, this costs to about 0.06 GBP/ 0.12 USD per job which is fine be me. Repeat, repair not production or even re-work production. And very little suck-it-and-see repair, tending to zero in on the errant component at the first or second target, minimal trace cutting (consequential bridging repair). At the moment about 20 percent lead-free jobs, as mainly old stuff still. In years to come where it becomes obvious that complete, all component, re-work is required then perhaps Ag would be too much of an overhead. Some of the bad joints i've seen in the last few years, you just do not come across with leaded solder. And we're talking about kit only a year or two old. eg totally unstressed (in temperature terms but subjected to vibration) 1/3 watt resistors (so no heatsinking at production) that you can pull out of the "solder" joint by finger force. No jobs have bounced back due to mixing of Ag and Pb-free solder (so far) Likewise I must have repaired pre-2006 boards , that had early Pb-free solder, using leaded solder in repair and likewise those jobs have not bounced back, so far. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ > Some of the bad joints i've seen in the last few years, you just do not come > across with leaded solder. And we're talking about kit only a year or two > old. eg totally unstressed (in temperature terms but subjected to vibration) > 1/3 watt resistors (so no heatsinking at production) that you can pull out > of the "solder" joint by finger force. Vibration is the killer with lead-free. Never mind the tin whiskers. But did you also know about tin pest ? I have no idea how much the temperature is affected by the copper (and silver for the rich) in lead-free but the Japs also use bismuth IIRC. " At 13.2 degrees Celsius (about 56 degrees Fahrenheit) and below, pure tin transforms from the (silvery, ductile) allotrope of ?-modification white tin to brittle, ?-modification grey tin. Eventually it decomposes into powder, hence the name tin pest. The decomposition will catalyze itself, which is why the reaction seems to speed up once it starts; the mere presence of tin pest leads to more tin pest. Tin objects at low temperatures will simply disintegrate. " http://en.wikipedia.org/wiki/Tin_pest Graham > > Some of the bad joints i've seen in the last few years, you just do not come > > across with leaded solder. And we're talking about kit only a year or two [quoted text clipped - 19 lines] > > Graham In the situation where you can just pull a component from a board, not desoledered, it is sometimes possible to see a grey powdery surface to the component, suggestive of tin-pest. And for using tin tinned new RoHS components destined for both old boards and Pb-Sn solder or new boards and silver solder, burr the tin off with a "diamond" cintride burr on a Dremmel, before tinning with the intended solder. A solid layer of tin is asking for trouble - turn to dust tin-pest. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ > > N Cook wrote: > > [quoted text clipped - 18 lines] > powder, > hence the name tin pest. These phase changes are called allotropes. > > The decomposition will catalyze itself, which is why the reaction seems to > > speed up once it starts; the mere presence of tin pest leads to more tin [quoted text clipped - 5 lines] > desoledered, it is sometimes possible to see a grey powdery surface to the > component, suggestive of tin-pest. No surprise. A guitar amp kept in the garage will see those temps. > And for using tin tinned new RoHS components destined for both old boards > and Pb-Sn solder or new boards and silver solder, burr the tin off with a > "diamond" cintride burr on a Dremmel, before tinning with the intended > solder. A solid layer of tin is asking for trouble - turn to dust tin-pest. And whiskers. The military etc are doing an enhanced version of what you describe. Graham |
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