18 April 2014

The Curse of Broken Traces: Repairing a Visual Sound Route 66 Overdrive

A music store owner in the area occasionally sends work my way (for which I am quite grateful—check him out at http://www.payettesmusictraders.com). One recent project was a Visual Sound Route 66 Overdrive, which is an overdrive and compressor in one pedal. The compressor side did not turn on. When you pressed the switch on that side of the pedal, nothing happened—the LED did not turn on and the sound did not change. He said it was probably the switch, and I went with that, a mistake that fortunately only set me back $6. 

I got it on my bench, checked it out, and it sure seemed like the switch, so I ordered one for $6 and didn't think much about it. The next day, though, I decided to have another look at it, because there was a sloppy jumper on part of the board (see pic below). Since a jumper often means a lifted solder pad or broken trace (or both), I started checking continuity along the circuit.
What the hell is this? Did the previous owner spill molten solder on the board?

When I got to the switch, there was very spotty continuity between two points that were clearly supposed to be connected. I poked the solder pad a bit with the meter probe and it moved. I think the copper trace was broken and disconnected, and being held in place only by the the thin green coating of the circuit board.

Two other nearby points were in the same condition, so I installed a couple of jumpers and replaced the solder blob in the picture above with new jumpers. That completely did in the solder pads (as you can see by the big brownish circles in the picture on the left below), so it wasn't as neat as I would have liked, but at the very least it is clear what has been done, since the jumpers are now lines that basically follow the circuit path, not just masses of solder.
Left: I replaced the solder blob with jumpers that will make the circuit much easier to follow for the next person who repairs this pedal. Right: The jumpers around the compressor-side switch that caused the problem.
As you can see, it sure isn't pretty on the inside (or on the outside, for that matter—this pedal's been ridden hard and put away wet a few times too many), but it works now and sounds great.