Technically there are capacitors in the power supply that can maintain a charge for many days (if not years). They
may have a bleeder resistor on them to slowly discharge them when the power has been disconnected for safety. It's still a source of danger though. My Amiga monitor would maintain a charge after it was unplugged, and would zap you if you touched the terminals of the power cord. It was like a static electricity shock on steroids.

<br><br>Dan East