Star Castle monitor (continued)

modessitt

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Ok, so I got my parts in, found a big stash of 2N5320 and 2N5322 transistors, and messed around with this again.

I'm using the CineFAQ troubleshooting steps because I'm popping a breaker with the monitor hooked up. I am testing with the ribbon cable connected.

Right now, I've stopped it from burning up parts, but I keep shorting the 2N3792 in the vertical amplification circuit between the emitter and the collector. The monitor will typically go for about 30 seconds before popping the breaker, and then I find the transistor shorted. Right now, that's the only part going bad.

Now, here's where I might have my problem.

At one point, I replaced the two .18-ohm 3W choke resistors because I had one that had some burn on it. Got the flame-proof kind. Well, while reading the CineFAQ, it mentions that they should be NON-INDUCTIVE and not wire-wound. So, I'm guessing I need to order the proper kind now.

But I'd like to know if this is enough to cause the problem with the shorted 2N3792 or not. If I need to order more parts, I'd like to do so while I'm ordering the right resistors....
 
wishing_well2.jpg
 
If you do not use non inductive resistors, the monitor will work, but your picture will unstable and jiggly.

you still have another problem, check all the transistors and diodes for shorts. Something is shorted and taking the 2n3792s out in the process.

mh
 
Thanks for the reply. I haven't been able to find anything else so far. I've checked every transistor and diode in that circuit, and have replaced quite a few bad parts. R118 WAS burning up, but hasn't since I replaced it with a flame-proof resistor.

I wonder if the chip is bad for that side? I could try swapping it with the other one to see if I start losing the other 3792..
 
It doesn't seem like replacing a resistor with a flameproof resistor is a good fix... there's probably a problem that's causing that resistor to burn up. Well... sure, it's not burning any more, but I think that's more of an effect of using a different resistor than fixing the cause (you could also replace it with a 100W resistor and it wouldn't burn either ;) ).

DogP
 
Well, I thought maybe the resistor was burning up due to a shorted 2N3792, shorted 2N5322, and shorted 2N3906. After I replaced the three shorted transistors, and changed the 47-ohm resistor to a larger wattage (as is recommended) - that perhaps I had tracked down all the problems.

Well, it made it about 30 seconds (without the yoke connected) before popping the circuit breaker. Found that only the 2N3792 was shorted (between emitter and collector) in the vertical circuit. Nothing else "appears" to be bad. I haven't found any other shorted or open parts yet...
 
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