thanx guys,

R32 is a funny one because in the past I was getting some readings from it on continuity test, today nothing.

In circuit the only reading I am getting on 2000K is 1985 but it takes 2 seconds before the meter returns the reading

This is in circuit so I know doesn't count for much, I am waiting for some smd resistor pack so until then I won't be removing it but im suspicious of this one.

As for now my bios issues, I hit a bit if a dead end its not a very popular board so can't find the exact bios anywhere, I found a bios for a greenpc vlb board with same chipset which works, the cache option saves in bios but still doesn't actually show in speedsys etc. Its not the right bios anyway so cpu doesn't get properly detected don't expect cache to either. But this shows my if my stock bios can't retain external cache on maybye bios has some corruption.

So not much I can do further here, keep hunting for the bios, change r32 when I get the parts

Thanks for everybodys input and tips, I think somebody actually said check tantalum caps early in the post, lesson for next time

I'm not sure your bios is corrupted : the fact that the other bios says cache is turned on every time might also be that the mobo don't check if it's actually turned on or not. It happens with some manufacturers especially when they did put fake cache on their boards

Yes this is a good point, I have been paying around with both the bioses original 4914 and green pc I got from a Russian site, they both don't show cache in the post screen or register in speedsys, now the post screen stopped showing the cpu speed, simply starting ms dos. So I think you are right the bios is ok

This motherboard only gets better and better. A interesting thing is the actual cmos chip is socketed.

Not much to it it saves and erases on my tl866, seems non corrupt. Anyway id say im on 90% complete here.

I might remove R32 later clean the pads and reattach it see if anything interesting happens.

OK gentleman, this just might be it!

I decided to look her straight into the socket and it wasn't pretty from close inspection.

A few of the pins were bent and deformed out of place slightly, possibly from me trying different cpus over the last 6-8 months of wrestling with this beast.

So I had to improvise the socket, pictures will tell better then words, but now I have Cache and cpu speed on post with the original bios with 3 different cpus so far.

A good few hours of gaming and benchmarking which I don't have at the moment will confirm this working 100% in the coming days Now some pictures

Congrats !!! Nice to see all this work finally paid !

I never thought those pins could be that damaged in a ZIF socket. Good to know! Thank you for sharing!

I guess CPU's with slightly bent/damaged pins would do this when inserted and removed a few times.

So glad you figured this all out. Enjoyed the journey!

Thanx for the comments, I have marked the thread as fixed now. I have had some time to use the system for 1 hour+ played duke nukem 3d for a while ran a quake time demo and some platformers without any crashes.

The cpu socket fix is a band aid solution changing cpus over is a difficult task and have had some funny errors come up during my final testing, cache, cpu speed disappearing at post and had himem.sys a20 error once until I reseated the cpu again.

So at some stage I will have to replace the cpu socket as a final touch but that is beyond this thread I think, everything is confirmed fixed now.

Fortunately, replacing a 486 socket isn't very difficult (still, you need to have quite the steady hand) at least it isn't surface-mounted 😵

But yeah I like seeing another old piece of hardware being resurrected 😀

Sorry to revive an old post. I have the same motherboard that was part of a lot i purchased . The board I have is missing the the bios rom. Just wondering if treeman still has an image of the rom and what type of eprom is on the board. Thanks

garyt21998 wrote on 2021-12-22, 22:59:

Sorry to revive an old post. I have the same motherboard that was part of a lot i purchased . The board I have is missing the the bios rom. Just wondering if treeman still has an image of the rom and what type of eprom is on the board. Thanks

I used a SST 27SF512 which is a direct replacement to the original chip. Note the socket on this board is longer then the chip, it came like that with the original bios. Have a look at the picture below for how it sits and the orientation in the socket

I have also attached a image of the bios, it would not allow me to attach a BIN file so I renamed it to ZIP. You will need to rename it back to *. bin then flash it using a external flasher, I used a tl866

Thanks, I completely forgot about this board, ultimateretro didn't exist at the time. I have added your bios here https://www.ultimateretro.net/en/motherboards/2118

Thanks for the help. much appreciated

no problem, let us know if it works