5160 BIOS swap question

[maelstrm]

Hello Federation,

Please excuse this noob question.

I'm trying to review a 5160 64-256KB board. Can I use the BIOS chips from a 5160 256-640KB board on a 5160 64-256KB board? The chip numbers are different between the two. I also see the two sets of BIOS chips have different capacities (32k vs 4k iirc).

Just looking to do a quick swap and see if I can get this 5160 64-256KB board to POST. If it's happy I'll go get another set of 5160 BIOS chips!

Thanks!

 

[modem7]

I'm trying to review a 5160 64-256KB board. Can I use the BIOS chips from a 5160 256-640KB board on a 5160 64-256KB board? The chip numbers are different between the two.

Lots of IBM 5160 information at minuszerodegrees.net

The answer to your question is yes.

I also see the two sets of BIOS chips have different capacities (32k vs 4k iirc).

Per [here], in the early BIOS revisions, U19 is 8 KB sized. Everything else is 32 KB sized. Not a concern.

 

[modem7]

If it's happy I'll go get another set of 5160 BIOS chips!

Early motherboard, so per [here], ensure that you do not get them on NEC µPD27C256 EPROM's.

 

[cjs]

Wow, that description about what's up with the NEC µPD27C256 is pretty interesting.

BTW, the reason for the two different pinouts on the ROM is to conform to one of the two different JEDEC standards: EPROM or RAM. (The 27256 EPROM has Vpp and A14 on pins 1 and 27; the 28C256 EEPROM and 62256 SRAM have A14 and /WE on pins 1 and 27.) So it was kinda crazy for IBM to tie the two together, rather than use a jumper.

(I have links to the JEDEC standards on this page, if you want to follow up on this.)