Frequency jump Collins s-line

[KB5MD]

I have a Collins 75S-3b receiver operating transceiver with a 32s-3 transmitter.  The transmitt frequency is off by 1 kHz from the receive frequency vfo setting,  not the same as it should be.  I have aligned  the receiver vfo and the bfo, but to no success.  Any ideas?

[WA5VGO]

Roy,

Try measuring the BFO crystal frequency in the receiver and the carrier oscillator crystal frequency in the transmitter. My guess is they aren’t the same. I suspect one or both of the crystal frequencies has drifted.