I found out the hard way that the Yamaha THR10 guitar amp has a fragile power plug. Mine fell off a table, the cord yanked, and the power plug shattered. My favorite travel amp was dead.
The internal power plug is hard-soldered to to an internal PCB. It’s not hard to replace, but it was a little tricky to find the right plug. This is a power plug with an internal switch. The act of plugging in the AC cord automatically disconnects the battery compartment. After some online detective work, I found that it’s Yamaha P/N V5095000, which is a relabeled SMK P/N LGP7031-0300.
Here’s what it looks like:
Here is the step-by-step to tear the amp down and repair the plug.
Remove the four chrome hex nuts in the front, all the other screws holding the case together, and all the knobs on the top. Also remove all the nuts and washers from the top of the amp.
Remove all the screws holding down the PBCs, carefully unplug all the connectors and disassemble the boards to access the old power plug.
Remove the old power plug and prep the holes for the new plug at location JK 501 on the PCB.
Solder in the new plug. It’s probably best to not use my lousy soldering skills as a guide, I’m out of practice. It still worked, even as sloppy as I am.
With the amp already apart, it’s a good idea to do the fix described at pickroar.com.
Reassemble the amp. Turn it on, plug in and play guitar!