Witchboard
Crossed Swords Squire
- Joined
- Aug 27, 2004
- Posts
- 182
Looking for a source for a couple of 27C1000 EPROM chips, or an alternative that will work. Needing them for S1 on Ghostlop.
Source for 27C1000, or alternative?
- Thread starter Witchboard
- Start date
Crossed Swords Squire
- Joined
- Nov 29, 2005
- Posts
- 4,275
Are you talking about the non-JEDEC compliant EPROM? (The one with OE* and A16 swapped?)
If so, the 27C301 is the same pinout.
http://www.arcadecomponents.com/catalog/item/2251646/1691687.htm
RJ
If so, the 27C301 is the same pinout.
http://www.arcadecomponents.com/catalog/item/2251646/1691687.htm
RJ
Witchboard
Crossed Swords Squire
- Joined
- Aug 27, 2004
- Posts
- 182
I'm not sure, but the information I found on the board is that I'm looking for a 27C1000 that has a different pinout as a 27C1001 or 27C010. I read that you can take either of the later chips and modify them with wires to make them compatible, but couldn't find any specifics. Thanks channelmaniac, I'll take a look at the 27C301 pinout and compare it to a 27C1001.
- Joined
- Nov 29, 2005
- Posts
- 4,275
The problem is that there wasn't really a standard for numbering of EPROMs and the pinouts in the early days.
Some manufacturers had 27c1000 that was the non-JEDEC and others had 27c1001 that was the non-JEDEC. Finally some settled on the 27c1001 as JEDEC compliant and others used the 27c010 as theirs.
The only way to know for sure is to check the specific datasheet from the manufacturer for the specific EPROM you have.
This is the suckage of dealing with 1Mb EPROMs.
RJ
Some manufacturers had 27c1000 that was the non-JEDEC and others had 27c1001 that was the non-JEDEC. Finally some settled on the 27c1001 as JEDEC compliant and others used the 27c010 as theirs.
The only way to know for sure is to check the specific datasheet from the manufacturer for the specific EPROM you have.
This is the suckage of dealing with 1Mb EPROMs.
RJ
andy251203
Hardened Shock Trooper
- Joined
- Oct 2, 2007
- Posts
- 430
I have some 27c010's I can sell you. PM me if interested. I can even burn them for you.
- Joined
- Nov 29, 2005
- Posts
- 4,275
andy251203 said:
Those are JEDEC compliant EPROMs... He needs the non-JEDEC type.
Witchboard
Crossed Swords Squire
- Joined
- Aug 27, 2004
- Posts
- 182
Thanks for the info everybody. In light of this new information, yes, I'm looking for the non-jedec chips. I'll give the m27c1000 a shot. Thanks again.
- Joined
- Nov 29, 2005
- Posts
- 4,275
Just beware that not all 27C1000 EPROMs are non-JEDEC on their pinout.
Witchboard
Crossed Swords Squire
- Joined
- Aug 27, 2004
- Posts
- 182
I'll be sure to compare then with the 27C301 pinout before purchase. Thanks again for all the info everybody.
Pas
Camel Slug
- Joined
- Mar 4, 2007
- Posts
- 507
The non-JEDEC 1000's and 301's can be hard to find. You can use the newer 1000's, 1001's, or 010's if you just swap pins 2 and 24 (I will recheck this when I get time but Im prity posative those are the right pin numbers...if you look at the datasheets its easy to tell). I have made a handfull of carts using this method by simply bending those pins up, soldering a wire to them, running the wires over the chip and into the hole the other pin usualy goes. Its not a perfect looking fix but alot of the time its what I had to do to make due to get the job done inexpensivly.
Witchboard
Crossed Swords Squire
- Joined
- Aug 27, 2004
- Posts
- 182
What I usually do in cases where I have to modify a chip is to modify an IC socket and install the chip into it. That way you can run the wires under the chip and not damage the IC. Looks a lot cleaner.
I'm finding the non-jedec chips are rather difficult to locate. Channelmaniac does have some 301's available for sale on his site. I may buy a couple from him.
Verification of which pins to modify would be appreciated. If I do got this direction, do you program the EPROM first, then make the modifications? Thanks.
I'm finding the non-jedec chips are rather difficult to locate. Channelmaniac does have some 301's available for sale on his site. I may buy a couple from him.
Verification of which pins to modify would be appreciated. If I do got this direction, do you program the EPROM first, then make the modifications? Thanks.
Witchboard
Crossed Swords Squire
- Joined
- Aug 27, 2004
- Posts
- 182
Thanks. Any tips on to program the EPROM before or after modding the chip?
Witchboard
Crossed Swords Squire
- Joined
- Aug 27, 2004
- Posts
- 182
Gotcha. I'll verify if non jadec is a switch on my programmer, or in the software. Thanks.