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Missing Bios Chip Soltek SL-54U1

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First post, by acl

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Hello

I was digging in my storage when i found an SL-54U1 SS7 Motherboard.
When looking at it, i remembered why i stored it without using it : missing bios chip.

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I found a bios image here : https://theretroweb.com/motherboards/s/soltek … -54u5#downloads

... But i have no experience in external bios flashing/replacement and i would like to fix the board and find a compatible chip.
So i'm not sure about what to look for.

The IC support looks like a DIP32, and there is an "256x8" label under it (256k x 8bit ?)
Am i looking for a flash chip ? an EEPROM ? Is there a standard for these bios chips ?
(a lot of questions)

With the right chip in hands, i'm sure to find either an EEPROM programmer from a friend or to hack something from an Arduino if it's a flash mem.
Any ideas ?

Thanks a lot !

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Reply 1 of 4, by weedeewee

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from looking at the bios file size you're looking for a 128Kilobyte eeprom or compatible. like a 27c1000 or a SST39SF010 or ...
though the motherboard might also support a 256Kilobyte chip, going from the labeling you've noticed. like a 27c2000, or a SST39SF020 or ...

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Reply 2 of 4, by majestyk

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Here´s another download source for the "U1" version - it´s probably the same BIOS though:

https://soggi.org/motherboards/soltek.htm

It´s 128K so you need a 1MB flash-ROM.

Reply 3 of 4, by acl

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Thank you very much !

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Reply 4 of 4, by acl

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Bios Fixed, Motherboard OK !

I used AT29C010A Flash chip. (5v EEPROM would probably have worked too)
I found a cheap lot of period correct BIOSs from 1997-1999. All DIP32 AT29C010A.
2€ a piece x 6 + 2 stamps for shipping (i will re-use the other for an Arduino project)

I already had a working Socket7 board, and it used the same chip for BIOS, so i came with the "hot swap flash" method.
I've already applied this method a a few times, with various results, but i gave it a shot.

Steps (for those not familiar with the procedure) :

  1. Have two motherboards
    • One working + the one with missing/broken bios
    • Ensure that the BIOS chip is the same/compatible
  2. Put the flasher software + the bios image on a DOS boot disk
  3. Prepare the working motherboard to boot on the floppy
  4. Before turning it on, loosen the BIOS chip from the socket so you can remove it easily (but be sure it still makes contact with the socket)
  5. Boot on floppy
  6. When the system is on DOS, remove the BIOS while the system is running
    • The BIOS is copied in memory, no impact on the system.
    • Do it carefully to not bend the pins
  7. Put the empty BIOS flash/EEPROM in place
  8. Flash the ROM using the tool (RTFM)
  9. Power off the system
  10. Swap back the chips.
  11. Success

Swapping the BIOS for flash :

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Testing the SL-54U1 with new BIOS :

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Board :

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The number one question now is what to to with this board... since i already have systems for this year/era (Socket7 MMX233, Slot1 Celeron 300A, Socket370 PIII700).

"Hello, my friend. Stay awhile and listen..."
My collection (not up to date)

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