Saga of the VOX AC15C1 Guitar Amp Repair and the Substandard Components Used
Your AC15C1 has blown up and no longer powers up. It’s time for a guitar amp repair. It’s the model with the all Chinese tubes made circa 2012/13. So, you think it may be the tubes failing and taking out the protection fuses. Usually you would on good odds for this to be the problem.
But No. On closer inspection your electronics engineer will find that if not already open the 180R resistors on the HT circuit and the 1kR to boot if unlucky are open circuit, or if not are getting really hot and smoking, that is if the fuse has not already gone.
WHY? Hmmm, aarrhh, the C52 and C59 10kpf ceramic capacitors installed at manufacture have gone short circuit. But why? Well it appears the components used have not more than a 100v rating (if you’re lucky) and the rating should be 500v. So, the poor things have given up the ghost and your amp is now dead because of them.
Here’s the schematic with the culprit components circled in this guitar amp repair.
- Replace these capacitors with 500v rated ones.
- Check and if open replace the resistors and you’ll be away laughing.
- Of course, replace any fuses that have blown with the correct ratings.
http://www.musicelectronicrepairs.co.nz