First post, by keropi
- Rank
- l33t++
Hiya!
I recently acquired a brand new Make-It 486 upgrade for 386sx processors. I opened it, installed it in my PS/1pro system and booted - I was not expecting any troubles since in the past I had a cyrix 486slc2/50mhz upgrade on this system and it just worked. But the old upgrade only had 1kb of L1 cache (and speed difference was nothing special for me so I just sold it again) - the new one has a TI cpu with 8kb of L1 cache and the speed boost is very noticeable (wolf3d went from 11.7fps to 29fps!) .
Long story short the upgrade is not working reliably, most of the time the system boots with an error code 102 meaning "system board error" according to the manual.
What I have tried is this:
- 386sx and upgrade pins cleaned
- tried on a 2nd spare motherboard I have, both have 1992 BIOS but one is labeled 08/04/1992 the other 26/06/1992 both behave the same with the upgrade
- tried swapping BIOS chips between mobos just in case
- tried only with the onboard 2mb ram, with a new CMOS battery after clearing and re-doing the BIOS settings
- tried with onboard or ISA vga
Nothing made any difference. The motherboard(s) in question is an IBM 87F4769 one:
Any ideas what to try next? Do I need a BIOS update for the TI486slc2 cpu? (the only bios source I know is on the IBM PS/1 Resource Page and I was the one that submitted the image 🤣 )
Open to all suggestions as I would really like to use that upgrade on this system. Thanks! 😊