This could be many things but a good place to look is the TX/RX and ATTENUATOR relays. These are problem areas in a lot of radios. This is a complicated radio and if you need to ask this question I would suggest you find someone that knows how to work on these. It will require a fair bit of skill to find the problem and replace the parts. The radio has a lot of surface mount components which are difficult to work with without causing more, and often, expensive damage.
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This could be many things but a good place to look is the TX/RX and ATTENUATOR relays. These are problem areas in a lot of radios. This is a complicated radio and if you need to ask this question I would suggest you find someone that knows how to work on these. It will require a fair bit of skill to find the problem and replace the parts. The radio has a lot of surface mount components which are difficult to work with without causing more, and often, expensive damage.