I recently made the decision to dive back into my old days and buy an old Atari 800 (wel the first computer i ever owned was an Atari 800xl). I recently bought a nice package off ebay. I have tested it now and played a few games. Now here is the problem. Sometimes the system seems to crash when i use the tape recorder deck. Sometimes when i press a play or rewind, etc button either the system crashes or sometimes i get random characters on the screen. As i say, this is only occaisionally not all the time. I suspect 2 problems:
1) Old age of hardware/maybe faulty

2) Or it is related to a power problem. I notice the PSU is not the original Atari one (it has an output of 9.5 volts which is weird).
Any, has anyone any thoughts on this? Many thanks for your help in advanced.
Regards