"Josh9.0" wrote in message
...
You need to establish some
facts. So far you have virtually none at all. Go get some and stop
guessing.

OK, How do I do that?
Thanks.


Make voltage measurements with your DMM. DC voltages first, then check for
ripple on those DC voltage points. If, as you indicated, the voltage points are
labeled, then start there... measure each voltage at its label.
Check ripple by using the AC voltage function of your DMM. Beware that some
DMMs are confused by a DC voltage, especially on the lowest voltage ranges. If
so, temporarily connect a 1 uF capacitor (having a voltage rating above the
voltages present in the organ) in series with one of the DMM leads to isolate
the DC from the DMM. The DMM should now give you a reasonably correct AC
voltage reading. The ripple voltage on a clean DC power supply point should be
less than 0.100 VAC (ideally, less than 0.010 VAC). If one of the power supply
points has much higher ripple voltage, then you can start looking at capacitor
failure.
Another cause of high ripple is rectifier failure, so you can't immediately
blame the filter capacitors for high ripple. A bad regulator can cause high
ripple, but you'll likely see a very wrong DC voltage as well.

If all are reasonably correct (+/- 5% unless you have more specific
documentation), then you have to look elsewhere.

If all the power supply voltages seem to be OK, the next most likely cause of
loud hum is the loss of a ground (shield) connection on an interconnecting wire.
This will require that you visually inspect each wire connection where it goes
off a board. If you find a broken wire, fix it and recheck to see if the hum is
gone.

Those suggestions should keep you busy for a bit. When you have found something
that seems out of reason and don't understand or know what to do next, then come
back with your questions. I'm sure we can get your organ back in service.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Life is like a roll of toilet paper; the closer it gets to the end, the faster
it goes.