Good troubleshooting job! Thanks for sharing your findings and solution.
73
Bob, K4TAX
Sent from my iPhone
> On Feb 10, 2020, at 8:57 PM, Gary Follett <dukeshifi@comcast.net> wrote:
>
> The Scout about which I have been enquiring showed a very unusual issue
> after I had replaced the final transistors (at the request of the customer).
>
> I did my usual ohmmeter reality check on all transistor pins just to ensure
> there were no shorts anywhere. I was surprised to find that one final
> transistor base showed the proper 100 Ohms to ground while the other one was
> >2 megohms to ground.
>
> I traced this through the PC board back to the balanced transformer that
> supplies the RF to the finals and found an open circuit between the top half
> of the PC board and the bottom.
>
> No amount of solder reflow corrected the problem so I passed a piece of wire
> through the hole in the PC board that is supposed to make this connection,
> soldered both sides, and things were now fine.
>
> I suspect this was the actual root cause of the customer’s issue with the
> radio’s output power.
>
> Oh well, at least he now has new finals instead of 40 year old ones…
>
> One for the books.
>
> Gary
>
> W0DVN
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