Resolved - Very High Video B+ - K6100 P329 PCB

SNESNESCUBE64

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I am not super familiar with these color vectors yet, but I am working on one right now. I've confirmed that the game board outputs correctly. I know the deflection board is working. When I turn up screen on the flyback I see picture (albiet it looks like shit and all of the vectors are white).

One thing I noticed is that the Video B+ is insanely high, I measured 280ish volts. That 2 is not a typo. I see that work has been done in this cage. It looks like they recapped it (with a dogshit kit, but I'll get there). This is throwing me for a loop. I see that the B+ pot looks new.

The LV circuit already has an LV2000 kit installed. I verified that the +/- 28V is there. One is a little low but I can adjust it.

One question I have though, and I feel stupid for asking, but what is the difference between the P316 and P329 HV cages? I see that one has an LED but this one isn't illuminated. This whole machine is a mutt of mismatched parts. Also, any ideas about the high b+?
 
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Q907 and R930 are missing on this board. I bet this is why it's not going into HV Shutdown.
 
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The 329 has an HV cut off adjustment pot, and usually is paired with the neck board that has the brightness control pot. P328 iirc.
 
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The Deflection board is 314 and the neck board is 315. This is definitely a mismatched monitor.
 
The Video B+ is generated by the timer circuit which is running at 20KHz. Video B+ is only 1/2 wave rectified.

Your multimeter may not be measuring it correctly depending on the capabilities of your multimeter. It would be better to check it with an isolated scope probe if you have one.

Check ZD902 and the resistors under it.

Then do the usual, especially if it has been worked on before, check all components are ok and inserted correctly. Check for any shorted or open traces.
 
This has been resolved, I am now measuring a proper B+:

-ZD902 was replaced with the wrong diode. No idea what it was but it wasn't the right part.
-One of the MPSA06 transistors was bad
 
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