B
bz
- Jan 1, 1970
- 0
An oscilloscope and signal generator are handy, but again is somewhat
hit or miss (for me) when I get into a transistor network as it's not
immediately obvious where the signal path is. It's almost easier in a
newer amp with IC's... what you end up doing is replacing an IC with ten
transistors in it because you know the problems's gotta' be in there
someplace if you've got signal going in and none coming out. If the IC
is not obsolete and/or proprietary and hence unavailable. In the past
I've used the scope to localize distortion which saves A LOT of time and
lifting of legs to test components.
If you have a scope (it need not be an expensive one or have high freq
response) one of the handiest trouble shooting devices I have is a curve
tracer I built that is similar to this one:
http://www.techlib.com/electronics/curvetrace.html
Mine is like the single range model.
Anyway, I find it very useful for locating bad transistors and bad gates on
IC because the 'knee' gets rounded or is absent on bad junctions.
Often, you can test 'in circuit', but sometimes you will have to cut some
traces to isolate the junction from caps or resisitors that are in parallel
with it.
A little practice with one of these, and a few 'reference junctions' to
compare with the curves you see, and you may love your curve tracer too.
--
bz 73 de N5BZ k
please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.
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