Simpsons PCB Bad Rom 8G. Screen is green and reboots after rom check.

PrimeTarget

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Simpsons PCB Bad Rom 8G. Screen is green and reboots after rom check.

Hey Guys,

I have a simpsons pcb that was working perfectly up until yesterday.

When playing it the colors went redish so I restarted the game. The rom test screen was green instead of black and rom 8G said BAD. After the tests are complete the game resets and does this over and over.


I pulled out the pcb and inspected the board. It looks like 8G is a "mask rom" because it is soldered right to the board not a socket?

Any ideas?

Thanks!
 
Yes it will be a mask ROM, but there are eproms of equivalent pinout that you can use as replacements if you get one programmed.

The green screen (or any mass colour change) can be caused by bad LS07 chips in the final section of the video stage.
 
Yes it will be a mask ROM, but there are eproms of equivalent pinout that you can use as replacements if you get one programmed.

The green screen (or any mass colour change) can be caused by bad LS07 chips in the final section of the video stage.

Thanks womble!

See I guess thats whats confusing. I would think that all I would have to do is replace the 8G chip and I would be good to go. But are you saying it could be something else down the line that is causing additional problems? I cant even get to the test menu to run the graphics tests. :(

Also I looked into getting a replacement chip. What I dont understand is do these companies have the info thats on the chips? Then they just pull up the right file and then burn a new chip?

I also thought about trying to re solder the chip as i have done some research on this board with people saying that sometimes its just a bad cold solder joint.

Thanks again for your input.
 
Well I did check the power supply and I am getting a good 5v. I did read that some times weak power supplies could be a problem.
 
Assuming it really is a bad ROM, all you have to do is download the ROM set intended for MAME, and burn the corresponding file to a chip and replace it. It's the same data.

-Ian
 
Does a simpsons have a battery on board? Dead batteries on boards will cause some odd problems to pop up.

Since the board is a multi layer trace board, You want to be extra careful in removing any IC cheap. This board is not the kind of board you want to learn how to replace an IC on.
 
No battery.

The problem with this particular boardset is hair thin traces that are easily gouged.
 
But this board failure occured while the OP was playing it!

What could fail that would affect screen color and the code execution?

That was the thing. My son and I beat the game and it continued to play in a redish tint!

On restart it never started properly again. I would think the game would boot and play in that green tint but it is a constant state of rebooting. Would that one rom cause that or is it a deeper problem?

Does any one recommend a good person that does rom programing?

Thanks every one for your help. My son is 3 and he is pretty upset that we cant play! :)
 
That was the thing. My son and I beat the game and it continued to play in a redish tint!

On restart it never started properly again. I would think the game would boot and play in that green tint but it is a constant state of rebooting. Would that one rom cause that or is it a deeper problem?

Does any one recommend a good person that does rom programing?

Thanks every one for your help. My son is 3 and he is pretty upset that we cant play! :)

KLOV user Steph runs hobbyroms.com. He can program most anything you want.

I just don't know what to tell him to program to fix your problem! Not sure it's a ROM problem.
 
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