Pioneer out of mothballs.

If your unit had long been sitting in hibernation, than you will need variac to power it own slowly. It's not tube unit, but nevertheless, first, I'd open the top and bottom covers, sweep it with clean paintbrush and/or vacuum, spray the whole thing especially rotary switches, all pots and knobs with DeOxit D5 (you may add F5  formula on mechanic components such as rotors of tuner and rotary switches ball bearings), than connect unit via variac and step-by-step increase voltage every 10...15 min to operating voltage. I usually do that within 3...4 steps i.e. within an hour towards the operating outlet voltage. Than I keep it running for an hour. SX-1280 has stand-by load resistors so running it unloaded isn't an issue -- just make sure that receiver is ON, but all speakers are OFF.

Thanks czar for your suggestions. I did clean it top to bottom, all the buttons,switches & knobs were cleaned w/CRC 2-26. I took the time to check for any cracks in the circuit boards & all the caps are fine. All the RCA plugs were also addressed.  Unit is as it was new. The only thing is that I didn't lube the dial knob & tuner assembly. I didn't know what to use.Any suggestions? I also didn't use a variac, all is working fine. I love this thing!
  

On tuner dial knob I'd use DeOxit F5. It's a lubricating formula.

That's what I used. Thanks. Now if I can get better FM reception I'll be a happy camper.

It has nothing to do with better FM reception.
For that you may need external antenna.