My amp suddenly going silent when volume knob touchedi have a ordered


I have a pre owned Rotel RA1070 that’s been working fine. Tonight, twice, I’m listening to jazz, wife sleeping, so I go to turn down volume a touch. The minute I touch the knob the sound goes dead. Amp, CD okay running, cables fine, speakers brand new MA Silver 2 .
I turned off the amp, waited 10 seconds, turned back on, everything running, sounding normal. Later on, I get up to turn down volume, same thing, sound goes dead. What’s happening? Seems to happen when I touch the control, before I even turn it down... Almost like a mini shock
sifter
mofimadness4 and xti16,

     You guys are right, deposit buildup just causes a scratchy static like sound but does not cause the unit to shut down.  
     Sorry, it was my fault.  I think I must have misunderstood the symptoms on the original post.
Thanks,
  Tim
@noble100
Wish I had a dollar for every post I initially misunderstood LOL!!
Sold my 1070, have had a few different  brand amps in here with no issues. Just picked up a nice sounding  vintage Rotel RA 1060.... same issue. Zap, no sound, LOL. Must be Rotel, other brands not exhibit, same living room, same conditions.