Electronics Forum / Equipment / April 2006

Does anybody here has the manual (user or service manual) for Philips
PM3320A ?
Dario.

Reading the datasheet of the 8253, I don't understand the sentence
concerning the mode 2 and 3 :
"In modes 2 and 3, if a CLK source other than the system clock is used,
GATE should be pulsed immediately following /WR of a new count value"

What are the respective pluses and minuses of these two signal generators?
I know the Racal has a very good reputation for low phase noise and signal
purity, but is a bear to work on, and that component level information isn't
available.

This is an older model with no wall wart.  Does anyone know the voltage
and polarity of the miniplug power supply?  How much damage could I do
starting with 5 v dc tip positive?  I have $40 in the unit, so I am not
eager to fry it.  Thanks for any help.

I've restored a 492 back to life after re-building the power supply. The
analyser seems to work except I'm not sure about  the Time/Div control. When
I set time/Div to Auto, the unit seems to work fine with the sweep rate
changing as I adjust Bandwidth Resolution. If I set ...

What fault protection is provided?
Would there be an overcurrent protection with timed reset?
The computer is an older Compaq (700 Mhz)  in the US.

Found an old HP 1200B scope on a junk heap.  No trace.  I think I'll try to
fix it up and give it to the next person who asks me what an oscilloscope
does :-)
Does anyone have a schematic or service manual for this?  Or even know what

My Racal 1992 is bringing up error 52 on the Channel A relay test (Relay C,
50 Ohm/1Meg switching), and error 56 on the Channel B relay test (Relay G,
x1, x10 switching).
Racal part numbers 23-7529 and 23-7528.

i bought a used scope and am looking for probes for it.
its my first scope and i mostly want to learn how to use it correctly
and become proficient in basic measurements.
its an old tektronix 5103N with a 5A21N diff amp, a 5A18N dual trace amp

Have a Lecroy 9450 scope with startup problem.
Anyone have a schematic of the power supply?
Phil J

My trusty old Tektronix stuff is getting pretty flaky and tired,
so I was looking for a replacement.  I was somewhat disappointed
to see that all the stuff on Tek's website is now digital.  The
reasonably priced models don't have enough record length to do

Many instruction booklets for domestic electronic equipment say do
not use cleaning solvents such as alcohol.
Is this advice given simply because they are trying to prevent
possible marking of the plastic casing?

What are the so-called "waveform computer" abilities of the 7854?  Did it
have any real usefulness?

I'm considering the purchase of a 760A.
I have a few questions:
1) The basic accuracy is 0.1%.  Does this mean that the selected output will
be within 0.1% of setting, or does it mean that the repeatability is within

Does anyone sell a dual or triple output power supply kit with volt
and amp panel meters, that I can build myself for my bench?