Question re EPROM equivalent to a 42-pin mask ROM

Solder

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Currently trying to fix an Operation Wolf 3 boardset. The mask ROM for the sound samples is partly corrupt.

This is a 42-pin mask ROM. Marked under the socket for it is:

2316000/32000

From my investigations I thought that the equivalent for this is a 27C322 EPROM, but on programming up a suitable EPROM with the data and plugging it in, the sound samples are then a mass of crackles (at least they mostly worked with the partly corrupt mask ROM).

Under MAME, the filename for the required file is: d74_01.37

http://maws.mameworld.info/maws/romset/opwolf3

27C322 datasheet:

http://arcarc.xmission.com/Tech/Datasheets/27C322.pdf

Am I using the wrong EPROM type?

Thanks
 
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If you read my post disregard it I looked at the wrong file - you need a 2mbit rom, not the 32mbit rom you're using! I think you need a 27C020.
 
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You are using the wrong ROM type. 27C233 is 32 megabit (4 megabyte). You need a 27c160, which is 16 megabit (2 megabyte).

You probably can't double up the 2 meg file to fit on the larger ROM....

Most sound processors (a la Neo Geo) use an 8 bit data bus. The 27C160 is a 16 bit wide chip, but can be read as either 16 bit or 8 bit wide. The 27C322 is ONLY 16 bit wide. Put it on an 8 bit data bus and the sound processor can't read it.

-Ian
 
Based on the file size of the rom image you should prob use a 27C512. The one you have is a 32 megabit rom and prob not pin compatible with the 512.

Jeff

Uh... it's a 2MB file size... which when you do a x8 you get 16Mb. Use the 27C160 EPROM.

Code:
Name       Size     CRC       Set
d74_01.37  2097152  115313e0  opwolf3

If you programmed the lower half of the 27C322 (which you would've by default with your programmer) then check the upper most address pin to see if it's tied low, high, or left floating. I'm suspecting by the noise that it may be floating when it should be tied low.
 
RetroHacker said:
You are using the wrong ROM type. 27C233 is 32 megabit (4 megabyte). You need a 27c160, which is 16 megabit (2 megabyte).

You probably can't double up the 2 meg file to fit on the larger ROM....

Most sound processors (a la Neo Geo) use an 8 bit data bus. The 27C160 is a 16 bit wide chip, but can be read as either 16 bit or 8 bit wide. The 27C322 is ONLY 16 bit wide. Put it on an 8 bit data bus and the sound processor can't read it.

-Ian
I don't believe that the data would fit into a 27C512, but thanks for the suggestion. :)

A 27C512 takes 64K of data and is 28 pins, a 27C322 is 42 pins (as is the original mask ROM) and takes substantially more data. :)

Yeesh. Does nobody read ANYTHING I post?

-Ian
 
Yeesh. Does nobody read ANYTHING I post?

-Ian

Sorry, I quoted your post by accident (meant to quote the post from orion331), nothing wrong with what you said at all. :)

Thanks to you and Channelmaniac, I did indeed need a 27C160. It works fine, but I'm sure that I tried a 27C160 when I last fiddled with this board and it did NOT work then. Must have been a dodgy EPROM .......... I dunno.

Still, all is now well, so many thanks guys. :D
 
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FYI I changed my post as quick as i could and still got it wrong anyway - sorry! Shouldn't be posting while doing other things at work.
 
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