Solid State Guitar Amp Forum | DIY Guitar Amplifiers

This oldish combo amp came in for repair last week...so before things got under way..The question I asked, was what's the main fault?  such as, blown fuse..odd sounds..low gain etc..etc.

The owner said he'd brought it 3rd hand for a cheap price due to it not being able to power up!
On inspection of the power amp stage it had been so badly reworked that the tracks started to break loose from the pcb on one side.  for those who've worked on these's amps would know it's a double sided pcb with on board psu.   

On checked it's schematic the power amp is 250w @ 4ohms use. I normally have spare module that would do the job..mmm..not this time so after getting the go a head to rebuild a replacement..

Next came fitting all the parts in and power up..all's well there...till feeding a signal through the front end and hearing distortion so a quick scope showed a over heated tl072 opamp at the main in put stage. possible damaged due to over driving it's in put with effects pedals.. to much i/p signal and the poor op-amp gets it!!

Anyway that's a happy customer with his amp back in action..next!