Sony KV-9200 Uneven Raster

[vol.2]

Originally Posted by Alex KL-1

1.6V with the set on? Very strange. Or the DMM are playing havoc with superimposed waveform, or really it have something fishy in Denmark...

If I am correct in assuming that Q512 is not conducting properly, then it's bringing the voltage down on the other side of L508.

The fact that it isn't conducting would be creating other complex paths to ground for the 112V present on the other side of L508, because the failed transistor is not letting current flow through L508.

Essentially, the current through L508 needs a path to ground to follow, but with Q512 dead, it can't reach the emitter of Q512, which is that path.

That's the way I understand it, but I'm far from an expert.

I think maybe Zeno could answer better, but I can promise that I'm not seeing any 108V on the collector of Q512. I have several multimeters, including an all analog one, and they are not seeing it. Measuring Q512 out of circuit reveals that it is *extremely* weak and the forward voltage is quite low on the collector junction specifically.

I would guess that this is a fairly common occurrence, since the HOT is getting hammered on constantly during scan time.