> Is it possible that the xistor tests good out of circuit because it's not
> under "load"? Could it be breaking down once voltage hits it? Did you
> try replacing it even though it tested OK?
>
> Keep us posted.
Hello all,
Finally got my Armor Attack working earlier tonight. After an engineer
friend filled me in on how Darlington pairs work (and also pointed out
the feedback section of the Cinematronics monitor circuit) I threw out
any hope of getting any definitive clues out of the scope. I
disconnected the HV, took the tube out of the monitor, and just started
switching parts between X and Y circuits to see when the problem would
move on the scope, which I put in XY mode and fed from the deflection
output. After a three or four swaps, I found the fault at Q209 - one of
the final predriver transistors.
The lesson learned - never assume ANYTHING with these things - except
that the problem is most probably a semiconductor. Parts tally for this
repair - two transistors in the XY deflection section, two in the Z
section, and a couple diodes.
Now if you'll excuse me, I'm off to play some Armor Attack and Star
Castle!!!
-Lewis
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Received on Sat Nov 25 00:30:27 2006
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