BLEEN wrote: ↑Sun Jan 11, 2026 4:12 am
If you don't mind, you think you can point to the area where or which caps might be offending?
I wouldn't just randomly replace stuff. You might make things worse, especially if the new caps have different characteristics. You really want to be testing the caps and only replacing them if they are bad. It's extremely unlikely that a cap which tests good is going to cause a big problem and you're better off leaving it alone.
Q502 is HOT. The collector of Q502 goes to H DY + (Horizontal Deflection Yoke Positive) and there's a whole network of components between them which is designed to modulate the deflection signal. The H Yoke signal is extremely powerful; it builds up huge voltage swings between the flyback and the yoke itself. When the yoke's field collapses, it sends a huge spike back towards the HOT and the damper diode stuff's job is to control that action. The caps in that area soften the blow. If any of the diodes are marginal or the caps are losing value or going up in ESR, it could create ringing or exaggerate raster brightness unevenness.
Remember that all CRTs have uneven brightness across them. That's a side-effect of the way the gun draws the lines from side to side. There are components in the set which are there to minimize it by evening out the trace.
The cap in that area are C507, 509, 510, 511, 527, etc, etc. None of almost none of them electrolytic. They are probably a mixture of ceramics and film. There's also caps on the other side of the H Yoke in the C515-C518 area.
Typically, these caps in newer sets don't fail, but you're obviously seeing something weird, so maybe one did.
You very well could go in and verify that all of them work. It could be some other component in the horizontal that is to blame. It could the HOT, it could be an IC, it could be a random diode or transistor that connects in some way and is sinking current. It would be very difficult to figure that out unless you had a scope and an isolation transformer. It would probably be very difficult anyway.
Then there's also the possibility that it's coupled into the video somewhere. I wouldn't even venture to guess in that situation. It's such a late-game set with so many ICs and such a complicated arrangement. Beyond what I currently can parse in a reasonable amount of time. I'd have to study it for weeks to figure out how it all works, and that's just step one in tracking something down. In cases like this, I usually end up soldering wires to the underside of the PCB and scoping all the waveforms while the set is running to look for something wrong. And that's another thing, you need an on-spec signal generator to produce the correct test patterns to even get valid scope results.
In any case, if you want to try poking around at the caps in the horizontal area to see if anything is obviously out of spec, this is where it is generally. I put little red arrows on the HYOKE connections from the edge of the PCB.
