Atari 400 boot up problem (I think!)

[pomegran]

Hi,

 

I live in the UK and just bought a couple of Atari 8-bit computers from a car boot sale (common in the UK). An Atari 800 which works perfectly and an Atari 400.

 

When I switch on the Atari 400, it makes a bleeping sound and shows the normal black border and blue screen. Sometimes Memopad appears when I press a few keys, sometimes not. It sounds like a fault.

 

Can anybody point me as to what the problem might be? Am I just booting incorrectly?

 

For information, I'm using the same power supply that the Atari 800 uses i.e. 9V DC.

 

Any advice would be very helpful. Would like to bring this little baby back to life!

 

Thanks.

Mark

 

 

[Paul Westphal]

Bad ram. try a basic cart, it accesses the first part of the ram.It does not have basic built in. take it apart and clean everything, including the connections on the card with a qtip and rubbing alcohol.You can get 48k ram for it at best electronics down in Cali for U$25.00 to make it run everything a 800 can. if you need help phalno@hotmail.com

[ClausB]

I had one with the same symptoms. It thinks the START key is pressed at power up and the "bleeping" is a cue to the user to start the cassette player. Good news is it's mostly working. Bad news is START is stuck. In my case it was stuck within the CTIA chip and the only cure was to replace the chip. Try it first with the keyboard unplugged. If it goes straight to Memo Pad then START is stuck within the keyboard. If it still bleeps then it's likely the CTIA or GTIA chip.

[pomegran]

Thanks for the prompt replies!

 

I do have a basic cart but it doesn't read it (the 800 was fine though so the cart is all good). Is unplugging the keyboard easy to do?

[pomegran]

Thanks for the prompt responses!

 

I've tried a basic cart and it doesn't work with that in (it works in the 800).

 

Is disconnecting the keyboard a simple job?

[+bf2k+]

800 power supply should be AC, not DC.

[ClausB]

Care is needed in unplugging the keyboard because it has a flex cable. Plugging it back in needs even more care. Easier would be to plug in the BASIC cart, turn it on, wait for the bleep, and press the BREAK key a few times to stop the cassette load. Then it should say READY. Does it? Then you can test BASIC and the other keys.

 

And yes the power should be 9V AC. It will mostly work with 9V DC.

[BillC]

Care is needed in unplugging the keyboard because it has a flex cable. Plugging it back in needs even more care. Easier would be to plug in the BASIC cart, turn it on, wait for the bleep, and press the BREAK key a few times to stop the cassette load. Then it should say READY. Does it? Then you can test BASIC and the other keys.

 

And yes the power should be 9V AC. It will mostly work with 9V DC.

I've never tried it, but I was under the impression that stock 400/800 machines wouldn't run with a DC power supply since 4108/4116 RAM chips also require -5VDC.

[pomegran]

800 power supply should be AC, not DC.

Yep, apologies. It is indeed 9V AC (Ingersol).

[Joey Z]

I've never tried it, but I was under the impression that stock 400/800 machines wouldn't run with a DC power supply since 4108/4116 RAM chips also require -5VDC.

Yes, it won't work at all with 9VDC unless it has a RAM card that doesn't need the -5V. In addition, the 12V line is used for the CADJ adjustment, and that uses a voltage doubler based on the AC from the jack. You'll get about 9V there instead, causing the colors to be off, which could probably be fixed with readjustment, but it's not really an ideal solution.