I'm trying to do maintenance on my stereo system and I know that capacitors will hold an electrical charge, but is there anything else that could shock me? I'm not sure this is the right place to ask this, sorry if its wrong.
If the electronic device is an old box type television, then you wanna watch out for the tube behind it as it produces a huge amount of current even after it's turned off. I had an experience where it hit my head with my brother's!
And then charged capacitors can do the same but I'm not sure if any can be as bad as that TV experience.
As long as the stereo is unplugged from the AC mains, it is mostly the capacitors that you have to worry about.
There are a few less common sources of unexpected voltage that are easy to disconnect:
An antenna going to the roof could get hit by lightning.
The Cable TV connection sometimes has an AC or DC voltage on either the shield or the center conductor, much higher than seems reasonable. The shield is supposed to be properly grounded at the entry to the building, but sometimes it is not. It can be a big surprise! The center conductor sometimes has DC on it for power.