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Seldom does the final AND driver fail. It is probably the final transistor.
Beware of phony final transistors. They are everywhere on eBay, and I would only trust the Eleflow brand. I have bought the cheap 'n phony 2sc1969 transistors from sources NOT on eBay too. Believe me; they are ALL phony.
Only one guy sells the REAL McCoy any more, and that is 'Eleflow'.
You can use either a 2sc1969 or a 2sc2312 transistor; they are interchangeable. The 2312 is even a little better than the original 1969 - BTW. You will also have to set the bias current ('mA') of the final. It wouldn't hurt to do the drive bias adjustment before the final bias either.
BIAS Current adjustments:
Set radio to CH 19 USB TX mode/Modulation Off.
Driver Bias: Connect current meter to TP7 (+) and TP8 (-) - adjust VR10 for @50 mA.
Final Bias: Connect current meter to TP7(+) and TP9 (-) - adjust VR12 for @100 mA .
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