Little screwup with R21 trimmer of the control board

Well, assembling my Shruthi-1 control board I made a mistake with the R21 trimmer and had to remove it. Well, to make the story short, it didn’t go well, and two of the solder points on the circuit board gone. What do you think is the best approach to deal with this? Can I lift the trimmer on the component side and solder there? Or maybe due to the trimmer height, that is not possible, and should try to retrieve the points from somewhere else in the board. Any tips?


The trimmer can be soldered on both sides of the board without causing much mechanical problems. If the board is really screwed up, you can still get away by using cables and making sure that the following connections are done:

  • Leg 1 of the trimmer to any point at ground
  • Leg 2 of the trimmer to pin 3 of the LCD module (see the image below)
  • Leg 3 of the trimmer to any point at +5V

Looking at mine, it looks like you could mount it on the top of the PCB instead of the bottom. But it depends on which side the PCB traces connect to. If the connect to the side the pads were removed from then it won’t work.

Thank you! The component side is in good shape, so I will solder the trimmer there, then. Those three solder points are small, and I noticed immediately I was going to have a bumpy ride with this one. :slight_smile: