I let others more expert people giving the needed answers so just some free not-expert thoughts about it.

When I was thinking and trying to flash old similar chip I think the starting point might be to know which kind of eprom is that, the exact model and reading the datasheet to understand it BUT I'd not touch that sticker if it's an UVEPROM that has the center glass on it. I suppose that If it's a UVEPROM it might need a burner that also have UV eraser if I understood that correctly and it's not said that can be reflashed after the factory flash at all and might be needed a blank new one, but who knows it might just be a normal EEPROM flashable by a mainboard IF the correct software could be found like usually happened with newer Socket7 mainboard. But that is a 486 PCI/ISA bios so it might not be easy to solve the problem and installing it in the wrong way sounds bad for its internal parts.
But it's a 32pin chip so it's a good starting point compared to the older 28pin one I got for my 486 PCI/ISA mainboard I could NOT find a way to flash and had to find what I supposed to be an equivalent who knows if working and yet to test similar eprom with the same sticker on it.

But as said I'm not expert and wait for others to have correct info about it. 😉

Easiest way to confirm if the chip is still good and to also flash a new EEPROM would be to get one of those USB EEPROM flashers.

TL866II will be just fine.
https://www.ebay.com/str/XGecu-Official-Store … cat=26414682010

If you do get one, make sure to get it from the official XGecu company eBay store and there is a ton of counterfeiting going on. My original one of an older model is a counterfeit one and, while it works, the official software detects it as a counterfeit.

If you get a programmer (I agree with the TL866 recommendation, it does the job well) then you might as well get a new EEPROM chip and burn the 4DPS BIOS to that one. Doesn't really matter if the original was a UV-erasable EPROM, you can usually find EEPROM equivalents that are much more convenient. Just peel the label from the blown chip to see the model number and find a compatible replacement.

TheMobRules wrote on 2020-08-04, 17:43:

EEPROM equivalents that are much more convenient. Just peel the label from the blown chip to see the model number and find a compatible replacement.

winbond w27c010 ( 128kb) are easy to find.

Thanks guys, here’s a pic of what’s under the sticker. Can anyone recommend which package I should go with from the eBay link?

Alternatively could I purchase a burned eprom off anyone while I figure out how to get setup?

There is an open source eeprom programmer that works for 28c512 chips. Used it to burn an updated bios for my 486 board which had a factory 27c512 eprom in it

Very cheap to build and powered by an arduino

https://github.com/TomNisbet/TommyPROM

cyclone3d wrote on 2020-08-04, 17:09:

Easiest way to confirm if the chip is still good and to also flash a new EEPROM would be to get one of those USB EEPROM flashers […]
Show full quote

Easiest way to confirm if the chip is still good and to also flash a new EEPROM would be to get one of those USB EEPROM flashers.

TL866II will be just fine.
https://www.ebay.com/str/XGecu-Official-Store … cat=26414682010

If you do get one, make sure to get it from the official XGecu company eBay store and there is a ton of counterfeiting going on. My original one of an older model is a counterfeit one and, while it works, the official software detects it as a counterfeit.

Thanks, I got one ordered from the Hebron, KY warehouse which I assume is actually Amazon and not far from me.

Now where to find a compatible EEPROM chip.

overdrive333 wrote on 2020-08-04, 18:37:

TheMobRules wrote on 2020-08-04, 17:43:

EEPROM equivalents that are much more convenient. Just peel the label from the blown chip to see the model number and find a compatible replacement.

winbond w27c010 ( 128kb) are easy to find.

Sounds like this would work, I see a few on eBay from China. Hoping to find some in the USA.

Doing more research it would seem a 27SF010 would the be the equivalent EEPROM, is that right?

Comparing the datasheets of 27SF010 and 27C010, they are pin compatible so it will work. Btw, you could download the Tomato 4DPS BIOS from Vogons driver library.

kalohimal wrote on 2020-08-05, 01:48:

Comparing the datasheets of 27SF010 and 27C010, they are pin compatible so it will work. Btw, you could download the Tomato 4DPS BIOS from Vogons driver library.
compare.jpg

Thanks for this! I found an Atmel part that I think will work.

https://www.ebay.com/itm/174256882088

AT29C020 is a 256kx8 part, it has an extra A17 address line at pin 30, so you'll need to check your board to see if the pin is floating, if so you'll need to tie it low. Alternatively, when programming the EEPROM you could duplicate the content to both upper & lower portion (128k x 2 to make up 256k) and you'll be fine too. Comparing to the 27Cxxx series EEPROM which is 12V program/erase, the 29Cxxx series doesn't need 12V and can erase/program with 5V.

kalohimal wrote on 2020-08-05, 02:40:

AT29C020 is a 256kx8 part, it has an extra A17 address line at pin 30, so you'll need to check your board to see if the pin is floating, if so you'll need to tie it low. Alternatively, when programming the EEPROM you could duplicate the content to both upper & lower portion (128k x 2 to make up 256k) and you'll be fine too. Comparing to the 27Cxxx series EEPROM which is 12V program/erase, the 29Cxxx series doesn't need 12V and can erase/program with 5V.

Thank you for this info, immensely helpful!

Wanted to say Thanks again for all the help on this thread!

Got my Zida 4DPS up and running again!