Atari 800XL - Nothing on Screen.

[MaXStaR]

I got my copy of Star Raiders today. Still the same result - nothing but a deep green screen. Looka like the machine is hooped. I found someone selling an Atari 800XL motherboard on eBay that they said came from a working machine, socketed ICs and everything. I'll work on the system more once it gets here.

[MaXStaR]

I got the replacement motherboard, board didn't work. But through swapping I found the original problem with my Atari 800XL is ANTIC was dead.

 

Also found the new motherboard (which was getting a green screen) had a Dead CPU. I may try to get replacement chips and toss the board back on eBay.

 

For now, I can play Frogger.

 

Thanks!

[mozartpc27]

with Star Raiders, you can still have bad ram, its just in the section SR doesnt use, same with PIA, and MMC... but it would signify the CPU/Antic/GTIA are good...

 

sloopy.

 

 

I have an Atari 800XL I picked up that is non-working currently. I've been through testing of the PSUs that came with it (there were two), at least one is outputting just a shade over 5V, then I tested all chips on the board, also all receiving 5V. So I found this thread and did this - picked up a copy of Star Raiders. Plugged it in, the computer still not working.

 

My question: does this then ISOLATE the problem with the computer to the CPU, Antic, or GTIA chips, or could it be anything on the board?

[sloopy]

No, it would mean the CPU/Antic/GTIA/ are good, and the MMU and PIA are atleast mostly good(if not fully good)... first thing I would do is replace the DRAMs and then troubleshoot from there...

 

 

sloopy.

[Rybags]

Star Raiders is a good choice if you suspect the OS Rom isn't good, runs as a diag cart so gets control quickly.

 

Probably a poor choice if you suspect Ram or memory select logic as it only uses the first 8K. Though all XL and newer machines have any given Ram access spread among either half or all the chips.

[mozartpc27]

Not sure what chip or chips are failing at this point. Took a stab at it with the Star Raiders cartridge.

 

sloppy, just to be clear, the way I understand this is if you plug in a Star Raiders cartridge and the cartridge is able to work on start up, this would eliminate the CPU, ANTIC, and GTIA chips as the cause of the problem.

 

Of course, nothing happened when I fired up the computer with the cartridge inserted.

 

Your response confused me a little, because it seemed to be saying that getting a black screen on start up with the Star Raiders cartridge plugged in indicates that the CPU, ANTIC, and GTIA chips are good, not bad.

 

So what I am asking is: which is it? Does a black screen on start up with the Star Raiders cartridge inserted indicate that that the CPU, ANTIC, and GTIA chips are likely good, or likely bad?

 

Sorry for my confusion.

[marcokitt2000]

I have a 600xl doesn't start to basic or start floppy disk,

I open it and check all the chips but the pia chip gets hot and replaced with a other and works.

If you have a other 800xl change all chips 1 at time but check first if there are chips get very hot than do not switch.

 

I hope you get it online .

 

 

 

Gr. Marco

[mozartpc27]

Checked temps of all chips when the computer is operating - none overheating.

[Joey Z]

Not sure what chip or chips are failing at this point. Took a stab at it with the Star Raiders cartridge.

 

sloppy, just to be clear, the way I understand this is if you plug in a Star Raiders cartridge and the cartridge is able to work on start up, this would eliminate the CPU, ANTIC, and GTIA chips as the cause of the problem.

 

Of course, nothing happened when I fired up the computer with the cartridge inserted.

 

Your response confused me a little, because it seemed to be saying that getting a black screen on start up with the Star Raiders cartridge plugged in indicates that the CPU, ANTIC, and GTIA chips are good, not bad.

 

So what I am asking is: which is it? Does a black screen on start up with the Star Raiders cartridge inserted indicate that that the CPU, ANTIC, and GTIA chips are likely good, or likely bad?

 

Sorry for my confusion.

black screen gives you NO information. Only if it works, do you know something.

[MonkeySchoo]

Hello ALL.

I have an 800XL with the GREEN SCREEN issue.

I replaced all SDRAM and MULTIPLEXER chips. Still waiting

for new/old ANTIC, ROM, CPU.

 

Has anyone figured this out yet?

The screen color changes to brown and blue when I turn the

screen GAMMA dial on the board.Unfortunately the second

800XL in the video is not socketed, so no chip swapping.

 

Here's a link to a video of my issue. Thanks.

 

Edited January 9, 2019 by MonkeySchoo

[+Nezgar]

Try swapping each of the main IC's one at a time into the working 800XL, to identify which of them might be at fault.

 

Left to right across the bottom: GTIA, ANTIC, CPU, PIA

Top right is BASIC (CO60302A)

under that is the OS ROM (CO61598B)

 

Edit: Woops, I missed that you said other 800XL is not socketed.... Well, you say you've got the ANTIC, ROM, CPU coming... OS ROM would also be high on the suspect list.

 

Have you reseated all those main chips yet?

 

See if you get a different behaviour or screen colour with the OS ROM chip removed.

[shoestring]

Not sure what chip or chips are failing at this point. Took a stab at it with the Star Raiders cartridge.

 

sloppy, just to be clear, the way I understand this is if you plug in a Star Raiders cartridge and the cartridge is able to work on start up, this would eliminate the CPU, ANTIC, and GTIA chips as the cause of the problem.

 

Of course, nothing happened when I fired up the computer with the cartridge inserted.

 

Your response confused me a little, because it seemed to be saying that getting a black screen on start up with the Star Raiders cartridge plugged in indicates that the CPU, ANTIC, and GTIA chips are good, not bad.

 

So what I am asking is: which is it? Does a black screen on start up with the Star Raiders cartridge inserted indicate that that the CPU, ANTIC, and GTIA chips are likely good, or likely bad?

 

Sorry for my confusion.

 

Is it blank or black ?. Yes there's a difference. Black would indicate video sync, blank means no video sync.

 

Blank would most likely indicate that the clock circuit isn't working. No clock = dead machine = blank screen. Only way to check for the correct clock signal is with a scope, it's one of the first things I check when a machine is totally dead. It's a rare fault but still possible.

 

Edit: Sorry, didn't realize this was an old post.

Edited January 9, 2019 by shoestring

[MonkeySchoo]

Try swapping each of the main IC's one at a time into the working 800XL, to identify which of them might be at fault.

 

Left to right across the bottom: GTIA, ANTIC, CPU, PIA

Top right is BASIC (CO60302A)

under that is the OS ROM (CO61598B)

 

Edit: Woops, I missed that you said other 800XL is not socketed.... Well, you say you've got the ANTIC, ROM, CPU coming... OS ROM would also be high on the suspect list.

 

Have you reseated all those main chips yet?

 

See if you get a different behaviour or screen colour with the OS ROM chip removed.

 

Thanks for quick reply. I have reseated ALL socketed chips, I've checked for continuity on each chip leg to make sure it's seated properly.

The only think that changes, is when I turn or even touch slightly the potentiometer next to the ANTIC, is the screen color from GREEN to

BLUE to BROWNISH. So there is a reaction.

 

When I insert the Ultimate CART it tries to read it, but the RED LED on the CART just keeps blinking.