Hi George,

Your oscillation stops, because the loop gain drops off.
Similar HP generators (the 200, that I have) do have a potentiometer
that adjusts the amplification, and hence the loop gain. Your generator
just might need a little bit of adjustment. If you have the manual, it
describes how to adjust that properly.
Another problem that you might have is the aging of the paper and
electrolytic capacitors in the circuits. The fact that the oscillation
stops at the lowest frequency, might indicate this. In this case you
just need to recap the instrument ;-)

Good luck, Peter

George wrote:
I have a HP201C oscillator, which mostly works. But, on the one freq range that
I need (x1), the output dies after a short period. This sometimes takes just
seconds, sometimes a few minutes. Other freq ranges are OK. A couple of
questions:

1. Is there some "all you've gotta do ..." fix for this problem?

2. How do you open the case up?

I have a schematic.

TIA,
George