2023-10-15 - Fixing Broken Loudspeakers I recently started trying to get better at soldering and general electronics repairs. Currently, I'm going through my collection of old speakers, most of which I got for free because people were getting rid of them. A lot of them had damaged cables and/or scratchy volume knobs. They're mainly cheap PC speakers that really aren't worth anything, but I thought it would be a fun project to fix them up and maybe even make some of them better than new. --- One set of speakers is USB-powered and had damaged cables, some of which I had already fixed before. I decided to actually improve the design on these and replace the soldered-on cables with connectors so the cables are separate. In this case, the secondary speaker already was connected to the main one with an RCA connector, but there was only a connector on the side of the main speaker. This cable was already damaged, so I would have had to replace it anyways, and I decided that I might as well add an RCA jack to the secondary speaker instead so the two speakers could be connected with a standard RCA cable[1]. I had to glue the jack in because it didn't have a nut to fasten it (although I made the hole so tight that it was already fastened pretty securely anyways). The cables coming out of the main speaker were still working, but I decided to replace them with proper connectors while I was at it. One of them had actually been replaced previously because it was broken[2]. I replaced the audio cable with a 3.5mm jack and the power cable with a 5.5mm/2.1mm jack (I could have used pretty much anything for this, but these were the first connectors I found). I then connected a matching plug to the USB cable that originally came with the speakers. Now there aren't any cables connected directly to the speakers, so the cables can be exchanged very easily[3]. The connectors I used actually had nuts to screw them on, but unfortunately I put the 3.5mm connector in a position where the nut didn't fit, so I had to glue it in[4]. This time, I also remembered to put on some heat-shrink tubing to make it all look a bit more professional. A small note: Many speakers have thin nuts behind the volume knobs that need to be unscrewed to open them or remove the circuit board. In this case, a nut had to be unscrewed to remove the circuit board so I could solder the connections properly. I usually use needle-nose pliers for this because none of my other tools fit into the small hole containing the nut[5]. --- The other issue with many old speakers (and other audio equipment) is scratchy volume knobs. There are approximately a million different methods people use to fix these. Some people just spray some sort of contact cleaner into the potentiometers, but apparently some of the chemicals people use are very aggressive and destroy the potentiometer completely over time. I really don't know what the best method is, but I eventually decided to just open them up properly, clean them with isopropyl alcohol, and then add some silicone grease to protect the inside from corrosion[6][7][8]. You can send me angry emails if you think this is a horrible method. I did this with two speaker sets. The first one required desoldering to open the potentiometers, the second one let me open them without desoldering. I actually first sprayed contact cleaner into the potentiometers of the first speaker set, which seemed to fix the scratching, but after reading about the dangers of doing this, I decided to open and clean them properly. Both speaker sets now seem to be working properly, so it just remains to be seen how long this state lasts. --- Anyways, that concludes a short description of my current project. It probably isn't really worth the effort considering that these are just cheap speakers that no one really wants, but it's better than leaving them under my bed in their broken state. [1] gopher://lumidify.org/I/phlog/2023-10-15-speakers/speaker_left_inside.jpg [2] gopher://lumidify.org/I/phlog/2023-10-15-speakers/speaker_right_before.jpg [3] gopher://lumidify.org/I/phlog/2023-10-15-speakers/speakers.jpg [4] gopher://lumidify.org/I/phlog/2023-10-15-speakers/speaker_right_inside.jpg [5] gopher://lumidify.org/I/phlog/2023-10-15-speakers/pliers.jpg [6] gopher://lumidify.org/I/phlog/2023-10-15-speakers/potentiometer.jpg [7] gopher://lumidify.org/I/phlog/2023-10-15-speakers/potentiometer_open.jpg [8] gopher://lumidify.org/I/phlog/2023-10-15-speakers/potentiometer_greased.jpg