In article ,
"RST Engineering" wrote:
Having said all that good stuff, maximum power means maximum heat means
maximum oxidation of the rheostat wire. Either a GOOD cleaning with a
toothbrush and contact cleaner or a little judicious application of very
fine (400-600 grit) wetordry sandpaper followed by a good cleaning to get
the sandpaper and oxide particles out of the rheostat will probably solve
the problem.


Jim,

Thanks for the input. I believe that I have potentiometer/transistor
pairs that perform the dimming function, rather than a true rheostat
(even though Piper still calls it a rheostat in the maintenance manual).
Based on what I've researched, I suspect that I may have a faulty
transistor. I will swap the old one with a new one and see if that
solves the problem.



JKG