Not too long ago I was given an Atari 2600 and a lot of games. It didn't work. Checked the power supply but it was fine. Vitaliy discovered that if it was switched on, then the power cord removed and re-inserted it would work! It still had life in it and wants to play some games!

What was strange was that as soon as you turn it off and try to turn it back on it wouldn't come up. The only way to make it work was by jamming in the power cord with the 2600 switched on. Thought maybe it was the switch so I took the whole thing apart, disassembled the switch, and cleaned the switch. No help.

Lots of googling didn't find anyone saying they had a similar problem. When I tested the 7805 inside I was getting the correct input volts but would get less than a volt out of it when it was switched on, but would get the full 5 volts when hot plugging the power.

I found some schematics online and thought maybe the two capacitors that are in the circuit before the switch were bad and were dropping the input voltage. I disconnected them both but no change. Only thing left had to be the 7805. Replaced it and now it works perfectly!

I'm still wondering why flipping the power switch didn't "jump start" the 7805 while plugging the power cord in does. Very strange. But whatever, the 2600 is completely working again and I don't have to fiddle with getting it to boot up!