CW Guitar Audio

Markbass CMD 102P combo was cutting out intermittently then had progressed to blowing the mains fuse. Found a screw and washer used to hold the main PCB in place rolling around which was causing the intermittent output issue until it killed the amp entirely. The remainder of the screws were finger tight. Although Markbass and their USA support were very responsive, they refuse to provide any service info or tech notes to aid in troubleshooting. These amps are made with switching power supplies and class D power amps making repair very complicated even with schematics. This one was beyond component-level repair due to power supply damage. They do offer replacement circuit boards and in this case the customer decided to proceed with that option brining the total out to almost the price of a working used amp. Something to be cautious of if ever considering any amp utilizing switching supplies and running class D. I’ve been getting a lot more inquiries across brands for these type of issues so it’s buyer beware. A well-built amp weighs a lot more but you can keep it running forever.