We need to get some posting consistency here. With half the respondents top
posting, and half bottom posting, it's becoming impossible to follow the
thread. Please all stick to bottom posting, as is the normally accepted
protocol in usenet newsgroups.

Right, Now that's out of the way. The voltages being quoted make no sense
against the drawn schematic that the OP provided. If pin 4 of the ribbon is
connected directly to the output of a 7805, then the voltage at that point
*must* be +5v on the unit that is working. It cannot possibly be at +30.2v -
period. This indicates that what you have picked as your reference ground to
measure against, isn't a valid secondary side ground. Bear in mind that the
primary side ground and secondary side ground on a switchmode power supply,
are very different. The valid ground for your measurements, should be taken
as the centre pin of the 7805. You might think that other places on the
board or within the circuit configuration are the same ground, but without a
manufacturer's schematic, you just can't be sure, so use a point that you
can be sure of or at least 99% sure of. I say only 99%, because
occasionally, you will see the output of a three terminal monolithic
regulator 'jacked' a little by the insertion of a diode or two in the ground
leg, but it's pretty rare on proper commercial equipment.

When you have reached a point where you can read a steady +5v on the
righthand pin of the 7805, then remeasure the other voltages, and let's see
if they make some more sense,

Arfa