NPC-RC for Cherokee NR-150
Step 1. Remove
the internal heatsink by unsoldering the final transistor along with the
heat sensing diode
Step 2. Make
sure that in place of L-36 is a plain piece of wire with a ferrite bead.
If there is a resistor with the ferrite bead on it, remove the resistor
and replace it with the plain wire and ferrite bead combination.
you are in this area of the board, you will see a two pronged support
for the mirror board at TP-7. Unsolder and remove the support. Using the
hole closest to the rear of the radio at TP-7 on the bottom of the board,
run at least 14 guage insulated wire from the hole to the emitter of the
AM regulator transistor, TR-51. Make sure the wire at the TP-7 end does
not touch the mirror board.
TR-50 and replace it with a 2SA1012 or 2SA1869 with the flat side of the
Step 5. Remove
C-189 and lay it aside for later use.
Step 6. Turn
VR-13 fully counter clockwise.
Step 7. Remove
R-237 and replace with a 100 ohm 1/2 watt resistor.
Step 8. Optional.
Remove R-249 if you have a spectrum analyzer AND know how to use the mic
gain correctly. Otherwise leave it in place. You won't notice much performance
difference either way and leaving it in place will result in cleaner modulation.
Step 9. Set
dead key to 2 watts. Radio should see at least 20 watts peak power.
Thanks to Billy Dean
Ward for his help with specific steps and to Bill Eitner for help understanding
the theory behind the modification.