30 Apr
2011
30 Apr
'11
11:55 a.m.
When I was looking at Bias and Interface board I
realised that the +5V must
indeed be coming from elsewhere as the tracks are not even connected
(directly) to the PSU motherboard. As you suspected, the output of E1 is 0V.
Well that certainly expalins why the relay isn't firing, and why the PSU
is dead (no power to a lot of the control logic).
What is the input to E1 (the 7805)? My guess is 0V again, which means
we have to do battle with an SMPSU (and one where a lot of the circuitry
is directly connected to the mains). On the other hand, it's worth
checking in case you're lucky and it's just the 7805 that's failed.
Incidentally, where are you based? I assume from the terms you use that
you're in the UK.
-tony