Help wanted with Xceed SE/306-48 EPROM

[rimmer]

I have this board that I'd like to put in the IIsi (currently, there's an Xceed Color30HR, and I feel I'm wasting a perfectly good SE/30 grayscale-capable card on the IIsi).

Now, my problem is that the sticker fell off the EPROM some time ago while the card was shelved, and I fear the EPROM has been wiped clean by light polution.

The card is at any rate not identified by the system any more, and my question is:

Does *anyone* have the hardware to help me re-flash the EPROM?

I *know* this requires another SE/306-48-board with the EPROM intact, but this is less of a problem for me, as the SE/306-48's are 12 a dozen on the internet.

Cheers, I hope you can help!

 

[waynestewart]

Which EPROM does it use? Should be marked with something like 2764, 2508 etc

 

[rimmer]

The EPROM reads:

Am27C64

-155DC

12.5V PGM

913K7NP

Cheers,

Anders

 

[Bunsen]

Feed some of those markings - especially the first line - into octopart.com and see if the part is still obtainable. Ditto ebay for old stock and pulls.

 

[waynestewart]

I'm able copy 27C64 EPROMs. I'm in Vancouver, BC

 

[trag]

You will be better off to replace the 27C64 with a 28C64 or any 28C part up to (I think) 28C512. I believe they all have compatible pinouts, but you should check datasheets to be certain. The only reason to use the larger capacity parts is that they may be more readily available.

The reason to use the 28C (or even 29C) instead of 27C is that it is an EEPROM (or flash) and not an EPROM and so does not have a window which can lead to erasing.

IIRC, the pinouts for the non-volatile memory chips change between 512Kb and 1Mb, so from 64K to 512K they are pin compatible with each other, but not beyond 512K. Again, this should be confirmed by looking at datasheets.

To reuse the 27C64 you currently have, it would need to be properly erased, either with a UV light eraser or by putting it out in bright sunshine for a long-ish period of time.

I could copy the chip, but I'm overwhelmed with other projects at hte moment and certainly wouldn't be able to get to it for a couple of months.