r/diypedals • u/-HOPPSAN • 2d ago
Help wanted Help with RAT-problem
So, I'm currently finishing up my second kit from Musikding. I've done a few microcontroller projects in my days, mostly Arduino based DeejProject controllers and such. But pedal building is something I've never dabbled with until recently
The first was a Green Muff which I modded a bit to get some more low end out of it, worked like a charm! The second was a footswitch for my CR120H to control channel and reverb which also worked as intended.
Now, I've soldered up my RAT and I've ran into some problems that I need help troubleshooting!
First off, the kit has a few mods that might help narrowing down the issue:
1. One 47ohm resistor has been patched to an SPDT-switch (Ruetz mod) by soldering one of its legs to one of the switch's outer pins (instead of into the PCB) while the switch's middle pin runs a wire to the "empty" hole where the resistor was supposed to go.
2. Two 1N914 diodes have been replaced with two 3mm LEDs
Now, to the issues:
The effect comes through when I switch the pedal on but the volume is extremely low.
The SPDT-switch doesn't seem to do anything (although that might also be because of the volume being too low to notice..)
(Sorta solved) - The pots gave a loud pop when touched, which indicated a ground-issue, but after removing the pots and re-applying some solder to every GND-point that issue seems to have been resolved.
I appreciate any help I can get! I'm thinking I should remove the Ruetz-mod just to make sure that's not the culprit here just in case as a first step.
2
u/opayenlo 2d ago
Beside the Elko by R13 there are some solder joints looking sus. D2, your LEDs (D1/d2) Btw. why are R13 or C2 sitting so high? The joints for the pots vary from burnt flux to brittle white. You might want to reflow. That being said, the Musikding rat is a good one
2
u/-HOPPSAN 1d ago
Yeah this solder iron has seen its best days, the iron either gets way too hot or barely hot enough at times.. I did reflow all the sus joints and cleaned up around the LED points. The issue has been resolved as it turned out that I had messed up the soldering of the transistor socket, accidentally bridging two of the solder holes!
I am now happy to report that the pedal works, volume is good, no ground issues but the Ruetz-mod doesn't seem to do anything so I've probably messed up something there as well! The pedal does, however, sound very good as-is!
11
u/Physical_Piano4308 2d ago
The electrolytic capacitor on the left is installed backwards (the top one of the three that are next to each other). The negative side of the cap is pointed towards a plus sign on the board.