When I power up subject receiver, I get a pop and some crackle after about 45 seconds through both speakers. After this, I hear a hum through both speakers and switching the selector knob from FM Stereo to either Phono or FM Mono and back to FM Stereo again, gets rid of the hum until the next time I power off then power on again. All switches/pots have been cleaned and the two main power supply caps have already been replaced a few months ago.

Comments/suggestions...?

Dirty power switch maybe or a leaky cap on pwr supply board? That is if you have tried cleaning the selector switch again.
The two main caps filter 60 cycle ....



Barney

Will check it out. Thanks.

Had a similar problem with my 2250. Used Radio Shak contact cleaner, didn't get better. Finally took it to a repair shop. The fix, cleaned the switches and pots with something a little stronger,(probably Deoxit), cleaned relay, (mine has a tone control switch) which he resoldered.

Got rid of the Rice Krispies! A few new caps and some deoxiting and she's singing like new!