Troubleshooting guide

Cinematronics Vector Monitor Repair Guide v.1.0
Page 42 of 53
Then I took voltage measurements during running and changed any part where a reading was
different from the other side. That wasn't helping.
Finally, I took out my logic probe (from Radio Shack, makes nice beeping noises :-)) and decided
to trace the input from the DAC side to the deflection side. I followed it through the 2N5210s and I
could actually hear through my logic probe, the deflection "chatter". So I followed that while
comparing to the other side occasionally, and it led me to the 2N5322 from the 2N5210s. There the
chatter stopped and was just a constant "low".
I replaced it, fired it back up, and now there was deflection chatter coming from it!
Hooking up the yoke and the neck harness, the monitor worked! I would tell you the part replaced,
but it would be meaningless, as Cinematronics tended to use different screening numbers for
different deflection boards (which really sucks, especially if you are trying to write a fix-it
document. The particular part is Q3 on some versions, and Q204 on others.)
Symptom Summary: I'm working on getting a Tailgunner monitor running. When I got it, it had a
couple burned out components. C3 or C4 (a 2.2 uF 35v tantalum cap) was popped open and R118
or R119 (a 47 ohm 1/4 watt resistor) was burnt to a crisp. C3/C4 is right next to the 7918 voltage
regulator which appear fine (tests very similar to a 7915 anyway) and R119/R119 is right next to
the large vertical deflection transistors (which also tests out fine). I've checked pretty much
everything else on the board and nothing seems bad.
Noting the above, you will want to replace the final output transistors (the ones mounted in the
heatsink) for the channel that the other components were burned on. It easy to tell which heatsink
as the connector is the one next to the 47-ohm resistor that burned. What usually happens is one of
the final output transistors shorts and causes the other components to burn.