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mitsubishi WS-55907 convergence and video



Jan 1, 1970
Hi. Got a Mits WS-55907 here. Odd problem if they are linked somehow,
otherwise 2 separate problems.

Anyway, first off, I will replace the convergence STK392-570 chips, as I
have good power to them.

Now for the odd part - no video, but does show the closed caption speech.
Also, no access to menu, just goes blank raster. Video good at rear jack
panel, but doesn't get to video drive transistors.

I did solder up rear jack panel and board connectors, which often fixes no
video, but not this one.

I did clean a bit of tube oil from signal board, but it appeared none had
traveled to or under any chips, was a small localised spot. Cleaned with
alcohol. No effect on video.

I have tube set and board set sprawled out on bench so I can run them up,
and find no missing voltages. All look clean, no grass or waving. Just this
oddity of no video.

I can give more details of voltages and such if needed, just wondering if
anyone else has seen this, are the two problems linked, or 2 separate
problems. Guy didn't say anything about convergence when I arrived, although
I noticed it right away. He just said video faded away.

Thanks in advance, Danny


Jan 1, 1970
Should have posted the fix earlier than now, but anyway, replaced signal
board with good used one from thrift store tv. 4 months later, still humming