Batboard

I have 2 VHF 45 Watt M120s with Dead a door nail receivers.
The radios TX perfectly. I can read and write to both radios.
I have squelch noise when the monitor button is held in for about 3 sec. (monitor mode)
These can't even hear an HT on the same freq 2 feeet away. Not even a busy light.
Suggestions? I don't have a service manual for these.
I do have a service monitor.

Thanks Tim K4TDO

Sounds like the 2nd Oscillator is off frequency.

Check for a 44.645 mHz. oscillator ON that frequency, if it's not on that frequency, and is high or low, your oscillator crystal requires replacement.

Sniff this oscillator with a sniffer probe attached to your monitor, it should be a strong signal, about +8dBm(-87 uV)'ballpark figure.

The crystal number is: Y52, # 48-80008K02(old manual number)

If you can't tune it in on frequency, tune to max signal and note the error frequency amount.

You could try heating the crystal to warp it and see how far, and in what direction it changes and by how much.

Regardless, if off evven by a small amount, it will need replacing.