I have a tremoverb that the tremolo is not working all I hear is a ticking that i can either speed up or down using the speed switch, I can not get it to oscillate. I can still get sound with the tremolo on or off. Michael at Mesa was kind enough to send me a schematic, so I opened it up and see nothing unusual. The only thing i see in common is a chip #555 that all the circuitry goes thru. I searched the archives but found nothing. Any help would be appreciated.