The pots to set the IRF510 bias on the uBitx and Bitx40 were backwards
from what most people would expect.
My best guess is that the sBitx follows this unfortunate tradition
since pin 3 of RV1 and RV3 is grounded, same as it was on RV2 and RV3 of the uBitx.
And it looks like the same Kicad symbol and blue physical part was used,
so fully clockwise for minimum bias voltage to the gates of the final is most likely.
I suggest you measure from the middle pin of RV1 to ground
with the power off using an ohmmeter, should show zero ohms
when gate bias is set to a minimum.
Jerry, KE7ER
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On Tue, Aug 2, 2022 at 08:55 AM, Niels Jalling wrote:
I have just burnet the PA IRFZ24's.
Where Is zero for the DRIVE_BIAS POT and PA_BIAS POT?
Is it where you expect it at anti clock wise end.
73 de oz9ny, niels
