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Sony KV-27S45 voltage regulation issue?
I’m back again with another Sony TV problem this time on a KV-27S45. (BA-4 chassis)
It seems to have a voltage regulation problem. There’s visible ripple in the picture, that gets worse when brightness and contrast are turned up. The B+ is around 131v and goes up to 133v after the TV has been on for a few min. PADJ in the service menu has no effect on the B+, even though the service manual states that it should be used to adjust the B+. According to the service manual the B+ should be 135vdc +/- 3v so I guess it’s technically within spec. I tried swapping out IC603 with a spare I had but it didn’t help at all. I’ve already replaced all the electrolytic caps in the power supply. I’ve tested several components but nothing has tested bad yet. Not really sure what else to try. Might be time to finally get a scope… Here’s the schematics https://drive.google.com/file/d/1pH7...Un2m5L0AX/view |
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