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PostPosted: Fri Sep 18, 2015 9:03 am 
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Joined: Sun Apr 20, 2008 7:06 am
Posts: 10
Location: Puerto Rico, USA
Hi guys I reacently decided to sit down and repair all 105 snes games I had here waiting for battery replacements, after replacing all batteries and testing I had around 20 games (Mario world,donkey kong country 1,2 and 3) that even with the new battery they loose the save after a few minutes. I honestly dont know what was wrong with them, all batteries checked OK and they had no visible damage on the board or sram chip. so I decided to go the sure way and remove the program rom chip from all the mario worlds and install them on some new Vegas Stakes game boards I had laying around, well suffice to say all worked 100% well after that swap. so I looked everywhere for replacement boards for the donkey kong country games (Single program rom Version) and I had to use some japanese Super Donkey Kong motherboards because problems appeared if I used other types of boards, here is all I did in order so you know exqctly what I did:

#1 Removed a Donkey Kong Country ROM Chip from one of the affected boards and installed it on a HIRom Board with 64k SRAM
Result: Game loaded fine but Piracy warning screen appeared when starting a game due to the board having 64k Sram instead of 16k
#2 Got some Japanese Super Donkey Kong 1,2,3 games to use as donor boards
a.> I made sure the japanese game was holding a save file or files before removing the japanese rom
b.> I made sure to match each game with the same (Ex, DK Country 1 Rom to a Super Donkey Kong 1 Board)
Result: After swaping the roms and testing them 7 out of 10 games retained the japanese save state even with the american rom instead
Fail: 3 games (Dk 1, 2 , 3) still loose the damn save state
c.> Replaced battery on those 3 games and still loose save, 1 of them looses it instantly, while other 2 retain it for a few minutes.

ALSO, I had a few encounters with games that hold save for a few days and they loose it later on, battery checks ok, its always a mario world, donkey kong country 1, 2 and 3.

I tought it may be something to do with the capacitor or resistors but I don't know what else to do, anyone has any idea what might be wrong?

thanks a bunch guys!

PostPosted: Fri Sep 18, 2015 1:52 pm 

Joined: Sat Jun 20, 2015 2:22 am
Posts: 17
1. have you used a volt meter to test if you have power going to the sram while the board is not plugged into the system?
2. if power is not going to the sram chip, are your solder joints done correctly? Use desolder braid to remove solder. scrub contacts with 99% isopropyl alcohol. use flux when resoldering. scrub contacts once again with isopropyl alcohol.
3. have you tried replacing just the sram chip? Could be that just your sram chips are worn out. Would be a lot easier to just order a bunch of replacement chips than finding donor boards if this is your problem.

PostPosted: Fri Sep 18, 2015 3:10 pm 

Joined: Mon Jul 02, 2012 7:46 am
Posts: 766
Do your bad boards have the MAD-1 decoder or the '139? If they're '139 boards, there are several passive components (resistors and diodes) that could have failed. If it's a MAD-1 board, bad solder joints would be my best guess. Other than that, try resetting the games without turning off the power, and if THAT doesn't work, then bad SRAM.

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