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Re: 7904 SMPS woes


 

Please disregard. I see where Jon mentioned the "hidden" ones.

Barry - N4BUQ

Did you include the tantalums on the backplane that are somewhat hidden behind
one of the interface boards (C60, C62, C64, C66)?

Barry - N4BUQ

Yep, as I mentioned that is all out of the machine and I pulled said tants on
the backplane - no love. Which were your bd ones?

I kinda been down these roads... looking for next road :)
- to recap (pun intended)
- - 15 bad
-- to quickly check if a particular board (vert, horiz, cal, Z) I pulled jumpers
to each one by one. no love
- pulled main interface board which as Jon said has tants all over the place for
-15V - I measured as many as I could find - no love at all.

I'm tryign to finish the isolation of SMPS itself VERSUS a shorted element in
the mainframe. I guess Ill try to load down the PSU and see if standing by
itslef its OK or not.

TY for the advice - it seems like I am following the manuals correctly as well
as having read the internet accuratelty for what to do.

Oran- the manuals say to use a variac to decrease input AC voltage to
troubleshoot the SMPS.

Thanks for the help!





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