Electronics Forum / Repair / April 2008

I've had this Sony CCD-FX620 since it was new in 1994. A while back I
replaced the smd caps on the audio/video board and it restored the poor
picture and audio back to normal. I powered it up a few days ago, ejected
the tape that was in it, and inserted a brand new one. Then it went ...

Good News!
This headphone amplifier has been REPAIRED and is now working
perfectly.
Here's what happened:

   I have a Compaq Presario 1200XL110 laptop (bought 2nd hand) with
bad display (display "wires" disconnected).  I used an external Monitor.  I
kept the laptop plugged into AC all the time and the battery installed.   I
had no problems the first few days.   Note: the laptop was on ...

I bought this ancient laptop (Toshiba T2000SX) on flea market.
It uses two batteries (second one is for BIOS):
-pa8725u (14.4V 2.2AH NiMH) shows 0,45VDC
-XZ0072P09 (6V NiCad) shows 0VDC

In the interest of clarification, I have added some information to the
schematic of the tape deck headphone amp that I'm having problems
with.
Some circuit paths are now labeled:

i am interesting where i can find some sort of  "most common" electronic
circuit diagram of typical PC motherboard, no matter if it is S478 or S462
type...
i am interesting in troubleshooting motherboards by electronic way...like;

My RCA rear projection TV has worked well after help from you TV
service people in January, 2005.  It has
a chassis number of PTK195AC and is model P60812BL
At that time I found that the surface of the PC boards had some of the

I am a home hobbyist who enjoys restoring vintage stereo equipment.  I
have a good working knowledge of electronic components and what they
do.  I have decent test equipment and good soldering skills, and most
of the time I am able to track down and repair a particular problem.

I have no cell service in my basement but I'd like to be able to take
a call without running up the stairs. Could I splice a 50ft extension
cord into my headset? I figure there are two wires inside for for
talking and the other for listening so it should work, no?

I posted about my Toshiba (CX32D60) a few months ago when I was going to
attempt a repair. The picture on it went to where people on the screen were
all squatty and cone headed. The general consensus was that it was a
vertical IC problem. I have some time now and have it torn ...

Using my Bluetooth-linked GPS unit with my iPAQ 2210 Pocket PC has the
serious downside that the 1000 mAH lithium-ion battery runs out after
3 hours or so, nowhere near long enough for a day's walking/hiking.
I'm considering buying a higher capacity battery (3300 mAH) but that

I've moved to N America from Europe and I'm changing some power connector.
My Question now is, when I look from the front on the connector, Ground on
the bottom, is the phase on the left or on the right? I unfortunately don't
have a phase tester handy.

I've got a small 12V DC .9 Watt 'muffin' fan (1.75"x1.75"x3/8").
It was the cooler for a video card's processor chip and was
frozen up.
I put a drop of oil into its sleeve bearing and it now runs

We just got an hp pavilion F50 lcd monitor without a power adapter.
(It's called a Tatung CLT-L50 but is supposed to be the same as the hp one).
It has a round power socket with 4 holes and is a little larger than a
ps/2 socket. The manual warns to not use anything but the ...

I hope this is an easy question to answer...
One of my older (dual-CPU) computers recently developed a problem.  Under
Windows, it was randomly giving all types of faults: IRQ_NOT_LESS_THAN_OR
EQUAL, PFN_FAULT, and many others that I don't remember.  Under Linux (which