[R-390] Repair of Crystal Oven for 1.0 Mhz Calibrator Crystal

[Paul Dulaff]

Everyone

I am repairing an R390 and I am having trouble getting the calibrator signal adjusted precisely beating with WWV at 10.000 Mhz as the adjustment runs out of range. I found that the oven for calibrator crystal is not working and may be keeping the crystal frequency low. I suspect the thermostat is not contacting.

Has anyone been able to open the thermostat and clean the contacts ?

Best 73's

Paul - WB2NMI