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QCX started buzzing all of a sudden after Q6 Change

 

Hi All,

Finally got around to change out the Q6 transistor, the initial one got toasted on initial setup. So now its an MPS751 as suggested. My qcx was from the initial batch.

Weird problem that just started happening is that when sending the sidetone seems replaced with just buzzing.... I know the sidetone itselves is fine because in practice mode its sounds just fine.

For Tx power it seems that it is putting about 1-2w output on 13v btw.

any help, tips or inputs greatly appreciated.

regards and 73,

Leo - PA1LDB
 

Hi Leo

I have seen buzzing sidetone here, when I had trouble with SWR or grounding. RF gets all over the place and some of it overloads something and creates that buzzing. Maybe you have something similar. Do you get the buzzing even when using a Dummy Load??

73 Hans G0UPL



On Sun, Jan 14, 2018 at 4:24 PM, Leo de Blaauw <L.deblaauw@...> wrote:

Hi All,

Finally got around to change out the Q6 transistor, the initial one got toasted on initial setup. So now its an MPS751 as suggested. My qcx was from the initial batch.

Weird problem that just started happening is that when sending the sidetone seems replaced with just buzzing.... I know the sidetone itselves is fine because in practice mode its sounds just fine.

For Tx power it seems that it is putting about 1-2w output on 13v btw.

any help, tips or inputs greatly appreciated.

regards and 73,

Leo - PA1LDB

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