2247A PSU Troubleshooting

Nicholas Keller

Hello, first post here and first real scope. A tech friend of mine gave me this in broken condition and said I could keep it if I can fix it. So here goes....

It doesn’t boot. Nothing happens when I turn it on.

I have disassembled the unit and visually inspected the PSU board as he said it had been repaired once before and was likely the same fault. He can’t find the service record. I couldn’t tell that anything had been replaced, and couldn’t see any obviously bad parts (swollen, leaking caps, for example).

I reassembled and powered up to test the power headers on the underside of the unit. They are all basically dead, however I did measure some mV on one of the high voltage pins.

I have a PDF of the schematic. I saw mentioned in a previous post about a record of some common issues with this PSU, but I couldn’t find the old post detailing these. Can anyone give me some suggestions before I attempt to trace signals? Is it safe to remove the PSU board and apply power to it even though some connections appear to be via other boards?

Thanks so much,

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