Just the thermal LED shows , also with all 5 amp modules unplugged from
the rack. Nothing looks bad , driver transistors and rectifiers, large
Rs and caps sloppy-test cold ok , fuses ok , etc.
Looks like the ST VIPer 12A , SMPS driver IC, data out there, powers a
donkey engine SMPS then the main when the cold side control logic says
ok to do so. I assume a schematic is not out there anywhere