Batboard

I have been researching some old threads about VHF GM300's with dead RX. I have one that is deaf as a post. Luckily I also have a working one for which to make comparisons with. I also have an IFR1000S service monitor to perform some basic tests with. I have narrowed some of this down to the 2nd oscillator as the good will emit a signal at 44.645 which both my scanner and IFR pick up clearly with a RX probe. The dead receive radio emits no signal at all. My question is which component is the 2nd oscillator?? I was able to find a part number of 4880606B02 in an old thread on here but cannot get a visual on what i am actually replacing. I feel pretty good as actually getting this far with it. I am ready to order this part if still available from my local moto dealer. Can someone verify that as the correct part number?

I also have two of these GM300 VHF radios with extremely low audio but good receive....possible audio ouptut amp???

Thanks to all who assist me and for any advice given.

Mike

Do you have the service manual?

I got the service manual segment from repeater builder. I was able to locate the crystal at U59. I also verified that both radios are able to receive at 455KHz by putting the probe right next to the crystal area, but the 44.645 only works on the good radio. The crystal on the bad radio also looks discolored at the base; much different than the good radio. I checked with my local M shop and they have the crystal at about $20.00. Are there any other tests I need to do and have I diagnosed it properly (as good as someone my level is at?). If anyone has a surplus of these oscillators I would by about five as I have five radios all exhibiting the same problem.

I think you got it...

Some crystals were mounted on the board too tight and the lead breaks. The little rubber insulator helps but I leave them a little loose and add a dab of Don's glue to keep the can from moving.

Common on Maxtrac and Radius too.

Take it out. If the leads aren't broken, suck all the solder out of the holes and put it back in. I have about a 80% sucess rate doing this. Seems like the joint crystalizes. Don't just reheat either it don't work.