Batboard

Is it possible/reasonable to swap a 40 W UHF PA from a Maxtrac onto a GM300? I read that the chassis cable is 6 pins for the GM300, presumable for the temperature sense...would this have to be grounded or tied to a voltage?

While I am on the subject, I have access to a few cooked Maxtrac UHF PAs...the operator would consistently talk and reset the TX timer. I'm wondering, given that knowledge, if someone here can point me to the likely point of failure in these PAs.
I repaired a Maratrac that was given a similar treatment, it was only the feedback network on the driver stage that was toasted (series cap-resistor-inductor).

Thanks,

Purpeman

On the UHF PA's, look at the solder around the output transistor. In particular look at the bypass caps between the base emitter/emitter collector junctions. Those PA's will get hot enough to flow the solder.

Thanks JMINN

JMINN wrote:On the UHF PA's, look at the solder around the output transistor. In particular look at the bypass caps between the base emitter/emitter collector junctions. Those PA's will get hot enough to flow the solder.

Exactly..
The solder will look grey and rough. Another known problem is the poor contact with the power transistor and the heatsink.
The heat transfer paste Motorola used drys out. And the heatsink pad that the transistor mounts to is not really flat.

You would have to disassemble the board/transistors from the heatsink.


Artic Silver heat transfer compound works really well.

Thanks Will.