Batboard

I have a CDM750 low band that will not turn on or off with its power button, change channels, or transmit or receive. the CPS reads it fine and I do get a good tone on power up. It also seems to program fine although that is hard to test with the other issues. I have a feeling it is in the control head but I am not sure. Any ideas??
Thanks
Paul

After reprogramming one frequency it does receive but the speaker audio is low and the volume control has no effect.

have you removed the head and cleaned the contacts