All good advice above. Just like buying a used car, parts to repair are needed to fix them when something needs to be repaired. Personally I have in the past year purchased a few high end CDPs. Got them so cheap that I don't care if they crap out in a year (won't be happy about it) but cheap to me is good. They had issues and I am able to repair them if I need to and can find the parts, otherwise off to the recycle bin. I only use them for transports and so far, the newer models just do not sound as good for what ever reason. Granted the ones I purchased were big bucks when they were new.
So you have to be realistic with yourself when you are buying an older used piece of equipment.
Happy Listening.