Bomber Man Board Repairs Bad Graphics

[GeekMan1222]

I been working on a Bomber Man board I picked up in a broken state awhile ago. I have been playing around with it on and off.

I finally completely reflowed the Graphics chip pins and got ALOT of results. I went from no picture to picture. Its not perfect yet and I get a Ram Error at this point. I tried reflowing all the pins again but it makes no difference at this point. Continuity to the SRAM's running to the GPU seem normal. As a result I am getting some garbled sprites.

I am wondering where to attack next. I would assume its a ram issue since the board is saying it is getting ram errors. But I cant seem to rule out maybe some bad rom?? I am still learning about the inner workings of digital circuit repair.

I have an Oscilloscope I am borrowing from a buddy at the moment. So If anyone has any suggestions let me know.

https://drive.google.com/open?id=1cNyudcvDM4tXfjOOzWlouvbUOAuNKGWV


I already moved the Daughter board off the main board a bit incase i needed access to those SRAMS's so excuse the jank looking temporary solution

 

[Hammy]

If you have checked over the custom soldering, replace the ram.

I had one the other day same fault. You can use 2 different types of ram and there is a jumper to select.
You can use larger ram for the repair, but make sure it's set correct.

PS. as you can see... also decrypted bomber man, so it should be able to get running on 'hasamu' boards

 

[GeekMan1222]

Thanks!

Wasn't sure which ram was responsible actually. Theres 4 rams running to that Nanao GPU chip. I'll go ahead and order some parts. I already have IC sockets that will work with this.

 

[GeekMan1222]

PS. as you can see... also decrypted bomber man, so it should be able to get running on 'hasamu' boards

So you soldered 2 3pin headers on the left and right of that custom chip? They had square via's looked like a spot for something to go.

I went ahead and added the headers now actually. What was the jumper configuration you found you need to use and did you have to cut any traces?

 

[Hammy]

The 2 added jumpers are for the security, you don't need them as you got the original processor

The ram jumpers are near the ram and are marked..
16K = 6116
64k = Sony 5863

 

[GeekMan1222]

So i replaced the 2 rams but im still getting the same thing, I checked all the vias and traces under the rams for continuity before putting the sockets on the board.

So now I am wondering if the other 2 rams are bad or its ROMS?


Also I realized that one of the pins to the GPU was shorted with solder to a ground pin after removing that short i got more garbage on the sprites but the behavior is still the same. At least i got luck enough to read the ram error messages when that pin was shorted

 

[Hammy]

You need to get that chip under a microscope before going any further.
After checking the chip's connections are ok ( it sounded like you already had ) Go for the other 2 ram.

Powering up the chip with shorts may of killed it...

-Carl

 

[GeekMan1222]

You need to get that chip under a microscope before going any further.
After checking the chip's connections are ok ( it sounded like you already had ) Go for the other 2 ram.

Powering up the chip with shorts may of killed it...

-Carl

I bought this board broken, didnt pay much for it at all. The pins on the chip were damaged, I managed to fix them up a bit but they were never shorted when i ran a continuity test. I am actually more worried some of the pins that were mangled are broken internally. I have bigger projects I have been working on my plate so its back to the bin for this one for a while I think. Though honestly I think it may be the other 2 rams or the graphic rom