Eprom Compatability question

Fatality83

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I am trying to convert my UMK board back to an MK3. I was told that the last row U17-U14 is supposed to be a m27c4001-12F1. Of course the only place I see that sells that exact chip is china or hong kong and I am not known for my patience so I am trying to find something compatible that is located in the US.

I found a ST MICRO M27C4001-15F1. Would this work in its place?
 
The difference between those two chips is the speed - recommended chip is 120ns response time, the other one you found is a little slower at 150ns response time.

Whether that makes a difference on an MK3, I don't know. I don't have one. In most cases that small of a speed difference doesn't matter (on arcade boards at least).

Brian
 
The difference between those two chips is the speed - recommended chip is 120ns response time, the other one you found is a little slower at 150ns response time.

Whether that makes a difference on an MK3, I don't know. I don't have one. In most cases that small of a speed difference doesn't matter (on arcade boards at least).

Brian

Ok thank you for this information. I was hoping that it would be the other way around. I found a company Freelance Electronics in CA that has 12 in stock of the -12's so I just ordered 8 of them. That way I am guaranteed they work. Thanks again.
 
Just found out, that the original chip I was looking for is meant for the revision roms which is not what I need. I am looking for the chips that go in U17-U14 they are supposed to be m27c4001c-100s Anyone know where to find these in the US?
 
Just found out, that the original chip I was looking for is meant for the revision roms which is not what I need. I am looking for the chips that go in U17-U14 they are supposed to be m27c4001c-100s Anyone know where to find these in the US?

In this case, you can use the 120ns chips. The speed of chips needs to be as fast as or faster than the processor requires. Since the processor is not changing, the chips shouldn't need to be faster. The only time I have seen this be an issue is with the speed of EPROMS on a CPS-2 board that has been phoenixed. Sometimes you need faster chips than what was there originally because of the elimination of the security code.

In your case, there isn't any decryption of the ROMs, so if the 120ns chips will work for one version of the game then they will work for all versions.

Brian.
 
In this case, you can use the 120ns chips. The speed of chips needs to be as fast as or faster than the processor requires. Since the processor is not changing, the chips shouldn't need to be faster. The only time I have seen this be an issue is with the speed of EPROMS on a CPS-2 board that has been phoenixed. Sometimes you need faster chips than what was there originally because of the elimination of the security code.

In your case, there isn't any decryption of the ROMs, so if the 120ns chips will work for one version of the game then they will work for all versions.

Brian.
I am sorry but now I am confused as a baby raccoon. I was told that m27c4001c-100s are supposed to be in there. I scoured the net for this type of chip and have come up with nothing for sale. Supposedely the m274001-12F is to be used for the revision roms only, so I cannot use this. My problem is finding a chip that is compatible and that will work in the appropriate slots. Sorry I am a newb at this chip business. I have been looking all over trying to find the answer. I am now going to have nightmares about IC chips coming after me when I sleep.
 
This is a Chinese seller on Ebay, but I have bought probably 100 EPROMs from him over the past year and anytime I've had an issue he quickly takes care of it.

The chips I have gotten from him are authentic and I've only had 3 or 4 chips that failed. He offered to replace them or refund my money.

Here is 10 of the 100ns chips : http://www.ebay.com/itm/New-ST-M27C...085?pt=LH_DefaultDomain_0&hash=item256c13d55d

Brian.
 
Thanks for the link. So those would be compatible? I have heard that someone used 27C040-10 in their place and they work ok to. Do you think these would work also or are they slower speed?
 
Thanks for the link. So those would be compatible? I have heard that someone used 27C040-10 in their place and they work ok to. Do you think these would work also or are they slower speed?

Its the same speed.. 100ns. They are what you are looking for... He ships quick too, you will only wait about 12 days to get them.
 
The "10fs" chips are for the Revision info. Every game data rom I have ever pulled off a wolf unit board has been a m27c4001-100." The Revision roms have varied with m27c040-10, m27c080-10, and m27c4001-10.

Granted, those are outdated, but I don't know what the replacement would be. The "10" roms are 4bm and the "100" roms are 8mb. The MK3/UMK3 game data roms MUST be 8mb (I don't know the speed), but the revision roms can be 4mb.
 
The other fellow that has been having the same issue told me that he took 27C040-10 roms out of his mk2, and burned them with the correct info and it's now working. I may just try and go this route since I at least know they should work.
 
do you have a chip eraser? why not just erase the bad chips or the chips on a spare board then reburn them with the appropriate data?
 
MK2 uses 4mb roms (with the expansion board). The "-10" would be correct.


The other fellow that has been having the same issue told me that he took 27C040-10 roms out of his mk2, and burned them with the correct info and it's now working. I may just try and go this route since I at least know they should work.
 
The "10" roms are 4bm and the "100" roms are 8mb.

zenomorp, I know you know your Wolf unit board stuff, but the number after the dash on an EPROM is the speed, not the size.

A 8mb EPROM would be 27C8001-100, not 27C4001-100. Any 27C4001 is going to be a 512kb x 8 or a 256kb x 16 4mb EPROM.

Brian.
 
Yes I am getting very confused, that helps clear some of it up but now the question of the day, which one will work.... Toplessz says he uses 27c4001-10f1s, your saying the M27C4001-10F6 27C4001 will work, Another person who was having the same problem says he used 27C040-10 from his mk2 and the problem went away.
 
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