Failed Attempt at Repairing the Valeton GP-100 Effect Pedal

This time I ended up frying my GP-100 effect pedal while trying to repair it.

Still, I learned quite a bit over the two days I spent struggling with it, so I decided to write this up.

1. Disassembling the GP-100

It actually wasn’t that easy to take apart, but if you just remove all the jacks, buttons, bolts, and screws on the top side, it will open up.

If you gently lift it, it opens easily, so don’t force it too much.

When I checked the power jack, it turned out to be a DC-005 barrel jack.

The outer diameter is 5.5 mm and the inner diameter is 2.1 mm.

2. Why the Repair Failed

I thought it would be as simple as swapping out the jack, but after replacing it, the unit still wouldn’t power on.

Turns out the jack section had aged, and the contact pad separated along with it…

I tried to do a jumper, but I accidentally applied reverse voltage and ended up killing the pedal.

The most critical thing was that I didn’t know the GP-100’s power supply center pin is negative.

The adapter below is a compatible power supply for the GP-100, and if you check the page, you can see the center pin is negative.

Well, the official documentation also clearly states that the center pin is negative, so I’ve got no excuses.

I was just being dumb…

The jumper method itself was simpler than I expected; you just need to connect the part indicated by the red arrow below.

In fact, what GPT first told me was correct, but I went off searching and overthinking things and ended up failing.

The answer was simple, but I took the longest way around.

3. Thoughts Afterwards

Electrical circuits seem to require more delicate skill and better equipment than I’d thought.

Based on my previous experience replacing DC jacks and micro USB (micro 5-pin) ports, I thought I was fairly competent, but real-world work wasn’t that easy.

It was a day that made me resolve to work with better equipment next time.