Here is one of the best summaries of 930 mods. My guess is your unit may have had many problems fixed by the factory. I would tend to follow the axiom "If it ain't broke, don't fix it." http://www.kkn.net/~k5tr/ts930fix/w6nl930.pdf I don't know the answer to your question about the resistors around the power supply. 73, Bill W4ZV P.S. Mike ZL1MH meant to say before/after S/N 310-XXXX...not 210-XXXX.