Quote:
Originally Posted by old_tv_nut
If it's not coming in on the previous stages, and all the caps are good, where else could it be but on grounds is what's puzzling me.
I think I would make a quick test of bridging a cap across C446, and triple checking it's the right value, and maybe bridging it to a different ground point on the circuit.
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C446 was a 10uf, 250V cap @85C. I replaced it with a 10uf, 250V cap @105C, Nichicon brand.
The ground side of the cap was solid and read as close to zero ohms as anything else on the ground plane. I removed the chassis board and made sure to measure it from multiple points on the chassis. The ground is solid.
Edit:
I tried doubling up C446, and I'm not totally sure, but it might have made a little bit of difference. It seems like the bars might be lighter. It may be possible that the original cap was a different value from the Sam's. but honestly, I've run into that too many times, and I always made a spreadsheet of each cap to make sure I put in what came out and note any discrepancies, so I kind of doubt it. Would increasing this cap's value significantly help things? I have a 100uf @250V I could put in there, but I don't want to screw anything up if that might be a mistake.
Do you think I should try sticking the 100uf cap in to see if it helps?
Also, I want to reiterate that this bars issue only shows up in the image of a certain brightness value (and therefore, I would assume voltage value). It's somewhere around 50 IRE I think. If the image is brighter than that, it won't show up, and if the image has bright areas and dark areas, it's only visible in the medium dark areas, and general only really visible in solid colors like you see in most video games.