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. Here’s how I fixed it.

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.

I bought it from Full Compass, here’s a link to the purchase page I found:

http://www.fullcompass.com/prod/241489-Yamaha-V5095000

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.

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Solder in the new plug. It’s probably best to not use my lousy soldering skills as a guide, I’m out of practice.

While I had the amp apart, I decided to make one additional fix.  While researching this power plug issues, I ran across an article at pickroar.com. They report an interesting bug in the design of the THR-10:

The Yamaha THR10, THR10X and THR10C are fantastic little practice amps, but they have a design flaw. When some of the wires inside get too close together, their signals interfere and a nasty high-pitched whining, squealing or ringing sound results.

My amp didn’t have this problem, but I did their simple fix anyway to prevent any future issues. Check out the full instructions at pickroar.com.

Once I had that item fixed as well, I reassembled the amp. Success!

Turn it on, plug in and play guitar!

Has this post helped you fix your amp? I’d love to know. Send me an email: david@fortc.com

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