Atari 400: Good one minute, gone the next

[FABombjoy]

Hello all,

 

Recently I rescued an Atari 400 from someone's quite dingy basement. After a good cleaning, I powered up the ole' machine and was playing Defender. Being new to Atari 8-bit computers, I was pleasantly suprised to be playing the game that I knew and loved from the 5200, only with a joystick that wasn't pissing me off.

 

So, I turn it off, change carts, and turn it on.... only, no dice. No power LED, nothing. Checked continuity on power & lid switches and they're A-OK. Take the meter to the power supply, 9.5-6 volts. Decided to test it under load, plugged it in to the 400 and it dropped to about 4-5V. The only other equipment that I own that uses AC is my Odyssey2, and it refused to work with the Atari supply, making me think that it is probably the PS. I'd try the O2 PS in the Atari, but the Atari supply is rated for a decent amount of current more.

 

Long story short... Should I check anything else before I try to locate a new power supply? Is there any comperable power supply that isn't Atari NOS? I'd really rather use something more modern... But I don't know what uses AC power supplies anymore.

 

As a sidenote, I had a 5200 PS go out on me between cart changes before. I'm cursed, I tell you.

[Nukey Shay]

Lick the end to be sure. j/k

 

Actually, if you are getting any power at all...couldn't you just try to light up a LED that costs less than a buck? If it doesn't light, there's your answer (though the cord leading into the power supply might have a broken wire or something). As a drastic measure, you could try chopping up the cord and wiring a new one.

[jjessop]

Take the top off and measure +12 vdc and +5 vdc off of the regulators bolted to the black anodized heat sink. I'm betting both will be way low and you probably have a bad diode in the bridge rectifier circuit. The console power LED operates off of the -5 vdc BTW. The RAM in an 800/400 use -5 vdc, hence the need for an AC input supply as it was easier to get a negative voltage that way

[FABombjoy]

After my post, I remembered that the NES uses AC, so I tried the 400 PS in that. Didn't work. I briefly tapped the NES PS on the 400 power connector, and the power LED came to life. I'm pretty sure is the Atari PS now.

[somePUNK]

i'm pritty sure my nes dsoen't work with my 400 power supply so i wouldn't count on that

[tyranthraxus]

I don't own a 400 but I had a similar problem with an 800 which might

be the same problem. On the 800 you have to flip a lid to get at the

cartridge bay. The computer would not turn on with this lid in the up

position! I don't know if the bay lid has a switch connected to it but

perhaps you did the same thing?

 

John