"Just Another Theremin Fan" wrote in message
oups.com...
I've tested all transistors with a VOM and they
seem OK.

God Almight.... VOM's should be banned from public use.....

The first thing to check with this kind of fault, is that the + and -
supplies to the front end are present. They are often derived from the main
high + and - rails that feed the output stages, by a simple power resistor
and power zener circuit. It is quite common in this type of arrangement for
the power resistors to go bad jointed, due to the temperature that they
typically run at, or the zeners to go short circuit, or the decoupling caps
across them to go short circuit. You will normally expect something of the
order of + / - 15v for the front end opamps.

Arfa