CDM 1550 High Power PA

[n5bbd]

Need help with PA problem. I have a CDM 1550 and it was working, now the PA is only putting out .5 watts. Is there anything I can check in the software. Be it the CPS or the tuner software. I have tried to adjust it with the PA Bias in the tuner and nothing seems to work. Is this a know problem with these radio's?

Thank you,

Pat

[35echo]

Under the top metal cover of the radio is a square or rectangular piece of silicon rubber. On the side that is against the circuit board is a black square that lines up with an interleaved trace pattern on the circuit board. This is the safety interlock that shut off the PA if the top is opened so it wont overheat. I would try cleaning the pad and circuit board trace with alcohol. This interlock is only on the LDMOS boards. The older Bi-Polar versions dont have it because the PA's are screwed to the heatsink. If dust/dirt/finger oil get in this area it can shut down the amplifier. If this doesnt fix the problem it will probably have to be benched.

Regards,
Allen

[n5bbd]

Thanks, I will look for this switch.

Pat