EricM wrote:

Here's a link to the schematic; after replacing CR1 and CR2A/B with
10 amp 600 V silicon diodes, when the relay closes to enable the 600V
plate voltage, the main power fuse F1 blows. I'm not sure I need
dropping resistors, because the output voltage on the 12.6 and -38
terminals is very close to what it should be. Is there something I'm
missing? http://img410.imageshack.us/img410/4691/1567pscb9.jpg

I'd disconnect the relay (S-1 and VS3) and comfortably check all other
voltages (value, polarity, ripple). If ok, I'd power off and check the
electrolytics in the 600 V circuitry (otoh, if they do not look
exploded, they are probably ok). Then the fault is somewhere else in
the device.

BTW, what is connectors 2 on CR4 and CR5?
Does somebody switch from 8 to 2 at some point?

Regards,
H.