[Boatanchors] Collins 75A2 PTO issue

[Rob Atkinson]

Glad you got it fixed and posted what was wrong here.  Thanks & 73

Rob
K5UJ

On Sat, Mar 20, 2021 at 3:15 PM Tree <tree at kkn.net> wrote:
>
> Following up in this - I found the root cause of the problem.
>
> Bill, N4LG gets to take a bow as he pretty much nailed it.
>
> There is a 1.5K Ohm resistor in series with the B+ lead coming from the
> radio chassis.  This resistor had cracked and was basically an open circuit
> (measuring over 3 Meg Ohms).
>
> It is a wonder this circuit could oscillate at all.  It was a 1/2 watt
> resistor - and I replaced it with a 1W version just because it was the
> first thing I found in the junk box and it fit.  It's tucked
> way down near the "bottom" of the chassis.
>
> Works fine now across the whole range of tuning.
>
> Now - to put this back together.  The last time I had it apart - I think I
> did something wrong and couldn't turn the dial indicator all the way to the
> right - needs another rotation of the circular dial
> which might have actually resulted in the band pass tuning being off by 100
> kHz.
>
> Thanks for the suggestions.
>
> 73 Tree N6TR