Atari 400 issues!

[Shinju]

Hey all!

 

I recently picked up another great Atari lot off my local craigslist, The lot consisted of, 1 Heavy Sixer, 14 2600 games and 1 Atari 400 with all the docs, 410 Tape drive, 4 games for the price of a supersized big mac meal.

 

Anyway, I tested the 2600 and games it all worked great, excited to play the 400 I tested that one last so that I can spend the most time playing it, I got it all hooked up and turned it on with Pac-Man in the slot and nothing the screen was showing a what appeared to be a solid black (probably brown since it was on my LED display) with a grey line on the right side. After about 10-15 seconds the colors shift to a green backdrop and flickering bars of color popping in and out of the display (no game play no audio).

 

 

I took it apart to see if maybe something came loose but all the chips looked well seated, the CPU and Ram boards were also well seated too, this appears to have the same issues as a 2 port 5200 I picked up a month or so prior.

 

 

Is this worth fixing or should I just wait for another working unit and use this one for parts? Also I have a lead on a 1200xl with floppy drive, do the 1200's play the same carts/disks as the 400/800?

 

Thanks!

[mimo]

Do you get memo pad on screen with no cart inserted?

I would still spend a bit of time pulling and re-seating the chips, ram board etc.

Is it worth saving? Well I would, but I am a 400 fan. An 800xl may serve you better though.

The 1200 xl is a lovely machine, but you will probably find the keyboard needs repair. There are some compatibility issues with the 1200xl, but not enough to put you off.

[Shinju]

Do you get memo pad on screen with no cart inserted?

I would still spend a bit of time pulling and re-seating the chips, ram board etc.

Is it worth saving? Well I would, but I am a 400 fan. An 800xl may serve you better though.

The 1200 xl is a lovely machine, but you will probably find the keyboard needs repair. There are some compatibility issues with the 1200xl, but not enough to put you off.

 

I get nothing on the screen but what was discribed above, I will tear into it again when i get a little more time I need to invest in a chip puller

[tep392]

Be sure to check contacts on both boards. I have a 400 that was DOA. The problem was the RAM board not making good contact in the slot. I cleaned up the contacts with a pencil eraser and all is well now.

[Shinju]

Be sure to check contacts on both boards. I have a 400 that was DOA. The problem was the RAM board not making good contact in the slot. I cleaned up the contacts with a pencil eraser and all is well now.

 

I did pull the CPU and RAM boards out but I did not clean the contacts, I will try that.

[Shinju]

Tried all the suggested techniques to see if I can fire it up but I got nothing. Something tells me that either the RAM board is bad and causing the CPU to Error halt or the CPU Board itself is shot. It almost appears as if there is a logo screen then it shifts over to the program/cart.

 

I also cleaned the pins for the boards as well (they were gold plated not the tin plated set).

 

It goes from a solid black screen then after a few seconds the screen goes to a dark grey then solid green, When these pop up local they are pretty cheap I might snag another one and swap daughter boards out and see.

 

Thanks for the suggestions!

Edited January 10, 2013 by Shinju

[russg]

Tried all the suggested techniques to see if I can fire it up but I got nothing. Something tells me that either the RAM board is bad and causing the CPU to Error halt or the CPU Board itself is shot. It almost appears as if there is a logo screen then it shifts over to the program/cart.

 

I also cleaned the pins for the boards as well (they were gold plated not the tin plated set).

 

It goes from a solid black screen then after a few seconds the screen goes to a dark grey then solid green, When these pop up local they are pretty cheap I might snag another one and swap daughter boards out and see.

 

Thanks for the suggestions!

I have an approach that isn't sophisticated. I'd take a good 400, or 800, or any socketed a8 and swap out the large scale integrated chips, the 40 pin ones, starting with Antic and GTIA. And the ROM chip. All you need is a working,

socketed motherboard to swap with. If you live in my neighborhood, I'd loan you a set of chips.

Edited January 11, 2013 by russg

[ClausB]

Did you try reseating the chips? Scrape off 30 years of corrosion by gently prying up both ends of each chip part way out of its socket with a small flat screwdriver. Then push them in again. It has worked for me.

[Shinju]

Did you try reseating the chips? Scrape off 30 years of corrosion by gently prying up both ends of each chip part way out of its socket with a small flat screwdriver. Then push them in again. It has worked for me.

 

I did that for the main CPU board chips and a few of the RAM chips. They were already pretty set in. I got another unit on its way to me that is untested so maybe I can Frank the 2 together and make one working unit.

Edited January 11, 2013 by Shinju

[Shinju]

I have an approach that isn't sophisticated. I'd take a good 400, or 800, or any socketed a8 and swap out the large scale integrated chips, the 40 pin ones, starting with Antic and GTIA. And the ROM chip. All you need is a working,

socketed motherboard to swap with. If you live in my neighborhood, I'd loan you a set of chips.

 

Thank you for the offer, that would be very cool of you if I was a local!

[russg]

Thank you for the offer, that would be very cool of you if I was a local!

I'm searching my chips. I don't have a 400, so I don't know how it is chipped. My 800 ROM board has three OS ROMs, C012399B, CO12499B and CO12599B. Does the 400 have a ROM board, or all chips go on motherboard?

The 40 pin LSIs are Antic, GTIA (maybe CTIA), POKEY, PIA, and CPU. On 800, the personality board has CPU, Antic and GTIA. POKEY and PIA are on the main motherboard. Since Shinju is getting another 400, he

probably won't need separate test chips, he can swap out the chips on the working one into the non-working one. Testing an 800, you can find which of the three boards the problem is on, it you have extra boards

The three boards being the personality board, the ROM board, the main motherboard and the power supply board and the memory board(s). That's five boards, three internal and two external.

Edited January 12, 2013 by russg

[Joey Z]

I'm searching my chips. I don't have a 400, so I don't know how it is chipped. My 800 ROM board has three OS ROMs, C012399B, CO12499B and CO12599B. Does the 400 have a ROM board, or all chips go on motherboard?

The 40 pin LSIs are Antic, GTIA (maybe CTIA), POKEY, PIA, and CPU. On 800, the personality board has CPU, Antic and GTIA. POKEY and PIA are on the main motherboard. Since Shinju is getting another 400, he

probably won't need separate test chips, he can swap out the chips on the working one into the non-working one. Testing an 800, you can find which of the three boards the problem is on, it you have extra boards.

the 400 has the 3 roms on the motherboard and no personality board. And you mistakenly said the CPU, ANTIC, and GTIA are on the personality board. That board is called the CPU board, the personality board is the one with the OSROMs. The POKEY and the PIA are on the motherboard. I think most, if not all, 400's were socketed.

[russg]

the 400 has the 3 roms on the motherboard and no personality board. And you mistakenly said the CPU, ANTIC, and GTIA are on the personality board. That board is called the CPU board, the personality board is the one with the OSROMs. The POKEY and the PIA are on the motherboard. I think most, if not all, 400's were socketed.

Thanks for clearing that up. I think Shinju said he had a CPU board. Is there a separate CPU board in the 400, the same as in an 800?

Edit:

I see a picture of the 400 inards. It has a CPU and RAM card slots in it. Can the cards be interchanged with 800 cards, can it have a 48K RAM card?

Edited January 12, 2013 by russg

[Joey Z]

Thanks for clearing that up. I think Shinju said he had a CPU board. Is there a separate CPU board in the 400, the same as in an 800?

Edit:

I see a picture of the 400 inards. It has a CPU and RAM card slots in it. Can the cards be interchanged with 800 cards, can it have a 48K RAM card?

the CPU card is interchangeable with the 400, and the ram usually is two, with a few small exceptions. by default *any* 48K card requires some amount of modification. 32K cards work fine in a 400 without mods though, and in an 800 I think they need a 16k card in the first RAM slot, and then the 32K card in the one immediately behind it. from there, 16K and 8K cards obviously work in the 400, and in the 800, any combination of those two works, provided they are in the front most slots.

[Shinju]

My 400 has 3 boards o

Inside, the main board, CPU and 16k ram boards.

[russg]

My 400 has 3 boards o

Inside, the main board, CPU and 16k ram boards.

I would guess you can put a 16k card in the front slot and a 16k or 32k card in the midddle slot. I have an 800 that has 48k that way. The 800 has three RAM slots. You did say you have another 400 on the way?

If you narrow it down to an Antic, I can mail you one of those.

edit: I'm getting these posts in real time, before I run out of edit time. I believe there may be some 400 with three slots two RAM and one CPU, if I understand Shinju. Maybe there are some with two and some with three.

Edited January 12, 2013 by russg

[Joey Z]

I would guess you can put a 16k card in the front slot and a 16k or 32k card in the midddle slot. I have an 800 that has 48k that way. The 800 has three RAM slots. You did say you have another 400 on the way?

400 only has the one slot. there is a 48K card that atari made which requires 4 wires to be soldered from the cart port to the ram slot. it needs the select signals for the upper 16K of memory and the two signals that disable (each) 8K of RAM for the cartridge to be mapped in.

[Shinju]

I would guess you can put a 16k card in the front slot and a 16k or 32k card in the midddle slot. I have an 800 that has 48k that way. The 800 has three RAM slots. You did say you have another 400 on the way?

If you narrow it down to an Antic, I can mail you one of those.

Yes, I bought an untested 400 for cheap so we will see if this unit works or start swapping parts between the two!

[Joey Z]

Yes, I bought an untested 400 for cheap so we will see if this unit works or start swapping parts between the two!

Well good luck. hopefully the unit you bought will work. And if it doesn't, then hopefully they don't have the same problem.

[russg]

Yes, I bought an untested 400 for cheap so we will see if this unit works or start swapping parts between the two!

 

Another thought, I'm sure you have done. With the mb and cards out of the case, the cart door switch would need to be closed. There's someone with an 800 that may be forgetting that.

OK, some more edit:

I get the same black screen and a vertical line in it when the personality (ROM) board is in backwards. It goes in the front slot with the chip side toward the rear. The CPU board also

goes in with the chip side to the rear. This is with un-encased boards, it is obvious which way to put the OS board in if it is encased. The RAM boards also chip side to the back.

Edited January 13, 2013 by russg

[BillC]

My 400 has 3 boards o

Inside, the main board, CPU and 16k ram boards.

Actually the 400 has 4 boards, you missed the power supply board.

[Shinju]

Actually the 400 has 4 boards, you missed the power supply board.

Lol you are correct sir!

[russg]

the CPU card is interchangeable with the 400, and the ram usually is two, with a few small exceptions. by default *any* 48K card requires some amount of modification. 32K cards work fine in a 400 without mods though, and in an 800 I think they need a 16k card in the first RAM slot, and then the 32K card in the one immediately behind it. from there, 16K and 8K cards obviously work in the 400, and in the 800, any combination of those two works, provided they are in the front most slots.

In the 800, the OS/personality board goes in the front slot and the RAM cards in the three back slots. All the boards, if with no case, the chips go toward the back.

[Joey Z]

In the 800, the OS/personality board goes in the front slot and the RAM cards in the three back slots. All the boards, if with no case, the chips go toward the back.

yep. I was thinking about buying an 800 before I bought the 400 BIN $49.99 (known good, came with games, joysticks). but since I was looking at 800's, I learned about the details about it too.

[tep392]

Lol you are correct sir!

 

That reminds me. Did you check the voltages on the PS board?