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tonyt76

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Hey guys I have a sunset riders PCB with bad 12K & 16K mask roms.

I purchased some AMD 27C400 e-proms but none of my programmers support these chips. Is there another chip that I could use instead that is more programmer friendly?
 
Hey,
What programmers do you have?
See if they support the Macronix equivalent, MX27C4100. You should be able to burn 27C400s with that profile.
 
Hey, I have the TL866CS & TOP3000
 
Last edited:
Forget the TL866.
You can burn 27C400s with the TOP3000 by choosing device MX27C4100 as suggested above.
 
I hope your problem is mask rom related. but most of the times, based on my experience while fixing konami boards, the problem resides;

a) customs which handle the addressing (gives false alarms in mask rom check screen)
b) rusted copper tracks or tiny rusted vias, especially hidden "under" the customs (again, gives false alarms)
c) failed logic ICs (especially fujitsu ones)
d) lifted legs of customs

To be honest, never saw a bad mask rom on konami boards (don't take it as a rule but this is what I experienced so far)

good luck...
 
To be honest, never saw a bad mask rom on konami boards (don't take it as a rule but this is what I experienced so far)
In my repairs I've replaced a lot of mask ROMs on Konami boards, so no that unlikely.
I think two members here ( @ekorz maybe and ?) had the exact same Konami game with ALL mask ROMs dead.
 
I’ve had bad mask roms on other Konami, never the whole board but hey. I don’t have a sunset riders maybe you’re thinking of someone else. Honestly it’s nice when it’s only a mask rom issue. I can fix that shit!

I will say the most frustrating thing is when your replacement rom turns out to be counterfeit. I’ve had that happen, and it left me fishing for other solutions for a long time.
 
No prob.

My Denjin Makai II / Guardians had more than half of its masks die (or had issues like bit rot). I replaced the rest preemptively.
 
I will say the most frustrating thing is when your replacement rom turns out to be counterfeit. I’ve had that happen, and it left me fishing for other solutions for a long time.
We had that problem with TMNT:TiT. Sound issues that just wouldn't quit and it turned out to be counterfeit eproms.
 
@ekorz, I wasn't sure who was concerned, couldn't remember, but found the thread now:

Repair Diary #4 - Simpsons (Work in Progress)

Game is Simpsons and members are @xodaraP and @ShootTheCore
Having pulled 2 of 5 of mine off, they actually both tested good against MAME. I'm now thinking @yavuzg is probably right and its a custom.

I've already repaired and am continuing to repair fairly extensive corrosion and it's gone from not booting at all and saying the final 2 mask ROMs were bad, to booting with errors and the mask ROM check reading them all with incorrect checksum

@ShootTheCore is slightly different, his mask ROM check is declaring all of his bad with 0000 checksum meaning the custom either isn't even trying to read them, or they are all stone dead.

I have however also repaired multiple Konami boards (TMNT and a Sunset Riders) where mask ROMs were shot, and almost every repair log I read for these games, the mask ROMs are shot, so they're certainly problematic.
 
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