Hi.
I got this MOBO with a missing BIOS chip.
I've found 'boot diskette' with software to flash BIOS but it does not contain bios images that I can use in programmer.
https://theretroweb.com/motherboards/s/ibm-pc … 71,-pc-350-6581
One of the board pictures at TRW is from GigAHerZ who is an active member here, maybe you can PM and ask for a copy of the bios....
Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun
You know what! I found that i still have that bios on my desktop! 😁
"640K ought to be enough for anybody." - And i intend to get every last bit out of it even after loading every damn driver!
A little about software engineering: https://byteaether.github.io/
Thank you !
I've programmed EEPROM chip.
The MOBO gives 'sings of live' 😉
Without RAM I get long - 3 short -long beep (memory or system board error).
Unfortunately, with memory installed, it is 'dead silent' (checked on 3 different RAM modules).
Maybe it is a matter of missing cache chips.... or there is a problem with MOBO itself.
Yes the missing cache could be a problem if BIOS does not accept 0 cache. The jumpers are only for 128k or 256k...
DO you have a Diag card ? It would help...
Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun
Horun wrote on 2024-07-01, 00:28:Yes the missing cache could be a problem if BIOS does not accept 0 cache. The jumpers are only for 128k or 256k...
DO you have a Diag card ? It would help...
I do have a diag card but without the riser I can't use it 🙁
I'll try to populate cache sockets - maybe this is the only problem.
One thing with cache bothers me...
There is bank_1 with DIP28 sockets marked 32kx8 and bank_0 with DIP32 sockets marked 128kx8.
There is no 512kB cache setting in documentation.
This modo can work without cache for sure. i had one in the past.
AlessandroB wrote on 2024-07-01, 08:45:This modo can work without cache for sure. i had one in the past.
Yup, the problem is not 'missing cache chips' related.
Inserting the cache did not change anything 🙁
It took me a while....
The main problem was a cold solder joint on the 82C802 chip.
I've resoldered all the pins of the above, installed the battery socket and the motherboard is working.
I also flashed the BIOS to the latest english version.
The board is picky about the BIOS chip, it worked on the AT28C010, but when I was trying to update the BIOS it reported an error about the chip being unrecognized.
Even though there was no attempt to flash the bios, a few first bytes in the flash memory were zeroed.
I've mounted Intel P28F010 and it flashes without any problems.
Thanks for the help to all participants.
Great ! Glad you were able to get it running.
Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun
Hi, are you able to share the BIOS update utility? I have the BIOS file but can't find any good links to download the Flash utility. Thanks
I'm not sure you even can flash it on board. You may need to get a dedicated programmer for that.
"640K ought to be enough for anybody." - And i intend to get every last bit out of it even after loading every damn driver!
A little about software engineering: https://byteaether.github.io/
Locutus wrote on 2024-07-01, 08:20:Horun wrote on 2024-07-01, 00:28:Yes the missing cache could be a problem if BIOS does not accept 0 cache. The jumpers are only for 128k or 256k...
DO you have a Diag card ? It would help...I do have a diag card but without the riser I can't use it 🙁
I'll try to populate cache sockets - maybe this is the only problem.
Probably too late to be any use, but I have a suspicion, which needs to be carefully checked against contacts on the board, specifically the first 4 or so in the riser slot, that you can put an 8bit card in the riser slot, but for 16bit and VLB the indexing is off.
Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.
Hi to ALL !
BitWrangler wrote on 2024-12-06, 13:59:Probably too late to be any use, but I have a suspicion, which needs to be carefully checked against contacts on the board, specifically the first 4 or so in the riser slot, that you can put an 8bit card in the riser slot, but for 16bit and VLB the indexing is off.
The mainboard was repaired and was working fine.
"The main problem was a cold solder joint on the 82C802 chip".
GigAHerZ wrote on 2024-12-06, 13:33:I'm not sure you even can flash it on board. You may need to get a dedicated programmer for that.
YUP - it has a flashrom onboard and BIOS can be flashed 'on board'.
I've flashed it with english BIOS and uploaded 'raw dump' for external programer:
download/file.php?id=196405
Taisho wrote on 2024-12-05, 23:21:Hi, are you able to share the BIOS update utility? I have the BIOS file but can't find any good links to download the Flash utility. Thanks
Sure, I'll try to do it tonight.
Sorry for the off-topic, but I need help.
I found a similar motherboard but without additional boards/modules.
Is a VRM-module required for all CPUs to run? I have Cyrix Cx486DX2-V66GP (3.3V), but I don't know if it's compatible with this motherboard.
ott wrote on 2025-09-05, 09:14:Sorry for the off-topic, but I need help.
I found a similar motherboard but without additional boards/modules.
Is a VRM-module required for all CPUs to run? I have Cyrix Cx486DX2-V66GP (3.3V), but I don't know if it's compatible with this motherboard.
Hi.
You will for sure need the VRM module for low voltage CPUs.
But... you can check this MOBO with 5V CPU.
Check out the picture of my board - VRM connector has to be 'jumpered'.
Locutus wrote on 2025-09-05, 10:34:But... you can check this MOBO with 5V CPU (check out the picture of my board - VRM connector have 'jumpers' installed).
Thank you very much for the clarification! I didn't notice the jumpers right away, but that's great!
It seems easier to find the 5V processor than the IBM's VRM module itself.
Thanks again!
You're welcome, glad I could help.
