To begin with a hint about looking deeper...In the last year, I have found two discarded CD changers. Both suffered from jammed tray mechanisms. You're probably already there; zip zip with a screwdriver reveals multiple CDs jamming up the works. Remove, and presto, both work perfectly. And it turns out that the Denon changer I fixed sounds better than the DVD player I'd been using for my CDs. You always learn something new.
The same happened years ago with a turntable spotted at a yard sale. "It doesn't turn." Grab, pedal the bike home, and yes, you've got it, lift the dustcover/mat and the belt had come off of the motor. Plink, and it worked for years.
If you do not yet solder, you are missing the same sort of "More" discussed above. I encourage you to learn how to read schematics, find and purchase vintage music integrated circuits if there are any you remember from your favorite synths, and go about building up what little support circuitry is required, to add such character to your modular synth setup. It's of course easier to begin with many of the PCB projects that are always cropping up; you can add to your setup at a fraction of the cost of many finished modules. The DIY forums at electro-music.com are an excellent place to begin! Cheers!