P1225 VHF almost deaf when scanning

[sataraid1]

What could cause a P1225 do go almost deaf, but only when scanning?

I have one that is behaving this way. When tuned to a single channel, it does fine, and performs identically to my other P1225s. When scanning it won't pick up a signal unless it's practically on top of me. It started out of the blue, and wasn't tied to any particular programming event, being dropped, etc.

Also, while we're on the subject of P1225s, most of mine need the switch/volume pot replaced. I have a mixture of radios with the older and later case styles, but only have a service manual for the older ones. Do they use the same part for the volume pot? Are they still available?

Thanks in advance.