Re: uBitx V3 low power continues


Problem located.

The scope pictures posted above showed no gain out of Q90 and I missed that obvious failure.  It seems that R83 measured out at some 1.8K when it's supposed to be 10 ohms.  I did wonder why the emitter of Q90 had close to the same scope reading as the base.  Now, with a proper R83 in place the waveform on the emitter is present, but low; meanwhile, the output of Q90 is now quantum levels above where it was.  RF out of the radio on 80m, 40m, 30m, and 20m are (about) 13, 12, 10, and 8 watts right where they ought to be.

Incidentally, I shoved a can-type 2N2222 into the Q90 spot some time ago to see if it would add the same benefit that changing out the 6 driver transistors gave. If anyone has a better suggestion for the application, please do tell.  Whether that swap "caused" R83 to open up is anyone's guess.

Thanks again to each and all. 



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