My 72 deluxe reverb started making some funky noises 2 nights ago. My tech got a hold of it, but can't get it to do the same thing. It is now working without problems. I don't want it to screw up in the middle of a gig. He suggested a "cap job" and is cahrging $150. Is that a fair price? Also, he said if I had any future problems out of this amp, he would fix for no charge. I thought that was cool.