Well, like I posted yesterday I've cleaned and
dismantled the PSU and
verified it's not giving out any voltage at all. There's evidence of heat
damage on what looks like ballast resistors next to a relay that must be
triggered by the 5V ADB line to actually powerup the PSU, but I'd guess
those things get hot anyways.
Yes, there is second 5V for standby for the ADB and batteries in the
IIfx does the rest for power up. Relay closes AC power for the
AC monitor socket and kicks the main SMPS into action.
Turn over and look at solder connections are they good? If not,
resolder them. This is odd because this SMPS in Mac II family
usually uses 2 sided fiberglass PCB not this cheap tan biscuit that
is commonly found in TVs.
again I guess that's down to operational heat
rather than excessive heat?
More like operational heat.