LiamDonovan
Hi Liam, thanks for your clear reply.
Unfortunately, I'm still having trouble with especially the startup of the Bela and the SuperCollider patch running on it.
I couldn't detect any short circuit lately. With the help of someone I consider 'expert' I attached a USB power analyzer and it didn't show any peaks or so, which would be the case if it would crash on that (he told me), even when it didn't start up once/twice when we were analyzing.
Now it sometimes refuses to start up (once every 20 startups or so, but that'd be the average of a random amount of times) > all the blue leds on the left side of the network socket remain off. It's quite hard to find the problem because it mostly doesn't show itself.
I also installed a new Bela, but this one also didn't start twice (out of maybe 30 starts). After a push on the reset button the patch started and worked fine. The (tin but isolated) casing doesn't seem to be the problem either, since I left it off to see if that would be it. (I mention it, though, because of Faraday cage issues, if they'd ever occur within metal casings?? 🙂 I really have no clue...)
As you mentioned I also learned that power supplies are quite important. This one is an Apple Model A1300 USB 5V / 1A. I made a Fritzing scheme of all the wiring I use, attached to this post. Please tell if you need anything else from me to think along again. Thanks so much for all your help!