Pioneer SX1280 repair

I am an amature audiophile, but I will try to help you.
This was one of Pioneer's top models way back when. As far as the popping noise, you could try tuner cleaner on the switches or buttons. Make sure you follow the directions on the can. And turn down the volume all the way when switching these buttons. This unit is probably jam packed with electronics so it might be hare to get to the switches. As far as the distortion. It could be that the coupling capacitors are dried out and may need replacing. It could also be a bad transistor. This is not a job for an amature. I would suggest looking in the yellow pages for a good hi-fi technician to do the job. Make sure you ask him the cost up front and what kind of warranty he (she) gives.