Okay, D27 was bad, I raised one lead and checked it and found it open. I measured the forward voltage on D28 and found it to be .204mv forward so I found another one that matched it and installed, now all is good and my SWR now shows quite accurately.
Interesting.. I wonder if the germanium diodes were matched at the factory to begin with. It may be part of the reason why SWR is a little off on working units.
Now to move on to next problem, crackly static which I have just identified, it was totally wiping out the 40 meter band while I was testing the SWR problem. I started by wiggling things to see what stopped it, when I got to the 5V buck regulator it would completely go away just by touching the module. The problem isn't mechanical, the module is actually generating the static. I seem to remember someone, (I think Evan Hand), saying there was some filter to stop this. Must search to find out.
Those converters are inherently noisy by design. I agree that some shielding would greatly reduce the noise. I could try 3D printing a cover and wrapping the outside in foil tape. I will ive this a try when I get things working with the replacement board. Good luck!
JJ
