atari 400 problems

[Tsukasa]

I just got an atari 400 off ebay, it seems to work, but when I boot up the BASIC cartridge that came with it, the keyboard doesn't seem to work. Help!

[+Mitch]

Does the keyboard work without the Basic cart?

 

Mitch

[+Mitch]

Does the keyboard work without the Basic cart?

 

Mitch

[Tsukasa]

Yes, it works without the basic cart. I can type stuff in memo pad.

[+Stephen]

Yes, it works without the basic cart. I can type stuff in memo pad.

988247[/snapback]

 

It could be a bad cart, or dirty contacts. What happens with the cart in? Do you get the READY prompt?

 

Stephen Anderson

[Tsukasa]

I tried cleaning the contacts on the cart, but it didn't help. When I boot up the cart, I get the READY prompt, but none of the keys on the keyboard do anything.

[+Stephen]

I tried cleaning the contacts on the cart, but it didn't help. When I boot up the cart, I get the READY prompt, but none of the keys on the keyboard do anything.

988307[/snapback]

 

I have heard of BASIC (and other) carts going bad before. That would be my 1st guess. My only suggestion would be to try a different cart on the machine. The computer is most likely fine though, since memo pad comes up with no cart inserted.

 

Stephen Anderson

[Rybags]

Can you do a System Reset OK once BASIC has started?

 

Maybe the cartridge just has a solder joint gone bad. Pulling them apart is easy enough.

 

I suppose it's only a 16K machine? If it's 48 or more, you could always just make a boot disk with Rev C BASIC on it.

[Tsukasa]

Once Basic is loaded, none of the keys do anything, including the reset button. I don't have a disk drive or any other software for it so I have no way of testing it. I checked the solder joints on the cart and they seem to be good. I noticed that the roms inside were socketed, so I removed them and re-inserted them to try to clean the contacts on the sockets. But that didn't make a difference. Also, just to see if it would work, I switched the roms in the cart. But strangely enough, I still got the READY prompt and the keyboard still didn't work. That really confuses me, I would think that the two roms in the cart were high and low roms, but then how come switching them didn't give me a garbled display or something?

[Albert]

Send me your address (via PM) and I'll send you another BASIC cartridge on Tuesday..

 

..Al

[Rybags]

Very weird that it would still have a READY prompt if you swapped the ROMs.

 

All versions run at $A000, and swapping the ROMs should stuff up the normal cartidge flags/vectors for starters.

 

A dodgy solder joint or trace could be the culprit? Do you have another 8K cartridge you can try the ROMs in? Or, you could take the ROMs out again and run a multimeter between all the edge contacts and pins on the chip sockets.

[Tsukasa]

I have a theory as to why switching the roms made no difference. I traced out the connections on the board, and found that both roms share all of the pins. The A12 line goes to the chip selevct line on each of the roms, I think that the chip select on the low rom is active low, while the chip select on the high rom is active high.

I think now that the problem is with the atari 400, not the cartridge. I made an eprom cartridge with the basic rom stored on it, booted it up, and it did the same thing. It gave me the ready prompt, but the keyboard still didn't work. I am at a loss at this point. I'm not sure what to do. I'll make another eprom cart with a game program on it, and see if that works.

How would I go about making a Basic Boot disk? I upgraded to 48K, so I have enough memory now, right?