[Hallicrafters] SX-71 2nd Oscillator Stability

[RJB]

Good morning to all Hallicraftees...

after several months of boatanchor absence i am back to working on my SX-71.
A few months back i installed an AADE digital readout (DFD) unit on this rx.
This unit works great; it is easy to calibrate, and reads dead right :-)

for one minute :-(

The DFD is driven from the first oscillator, ie the variable one. This is
reasonably stable, which means that the DFD readout stays reasonably steady
over, say a 30-minute period. However in this period the radio itself may
have drifted 2-3 kHz. Reason appears to be that the 2nd osc has a slow but
persistent drift.

Yeah i know - serves me right for installing digitial readout on a radio
that wasnt designed for it... Hey, before you laugh *too* loud, i have used
DFD's for years on my Hammarlunds with excellent results.

So... anyone else encountered stability problems with the SX-71 2nd osc??
Any remedies??

FWIW i have replaced all resistors and all bypass caps on this rx (maybe
this is the problem).

thanks in advance for any help

Bob Bennett, Maple Vly, WA