Sounds to me as if the Scout has a 7810 or LM340-10 regulator for the
VFO. That regulator needs about 2.5 volts headroom input to output to
maintain regulation. Very likely the TO-92 version 78L10. I have no
Scout and no scout manual to see. Perhaps that regulator could be
replaced by a LM2937ET-10 or LM2940-10 or a series resistor and a TL431
family programmable zener diode. The LM29xx family works with down to
0.6 volts drop, the TL431 would work lower though a bit less efficiently
than the series regulator. The TL431 programmable zener diode is a far
better regulator than any plain zener diode.
73, Jerry, K0CQ
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