Do you have the regulator board?

https://theretroweb.com/motherboards/s/fic-486-pvt-rev.-b1
https://theretroweb.com/motherboards/s/fic-48 … vt-rev.-b2#docs

dominusprog wrote on 2024-06-20, 10:35:

Do you have the regulator board?

https://theretroweb.com/motherboards/s/fic-486-pvt-rev.-b1
https://theretroweb.com/motherboards/s/fic-48 … vt-rev.-b2#docs

I don't know what the board without the regulator looks like, but from what i can tell, that corner looks like it has one (looks like i have the B2 revision). I can set the voltage to 3.45v, the board posts, but shows the cpu as 80487SX at 66mhz....

Forgot to add the picture.

Try this

1JC1=1&2 JC2=1&2 JC3=1&2 JC4=Open JC5=1&2
2RN16=Installed RN17/RN18/RN19=Not installed
3JCV1/JCV2=Jumper together pin 2 on JCV1 and pin 2 on JCV2 CN6=7&8&9&10

dominusprog wrote on 2024-06-20, 11:18:

Try this […]
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Try this

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1JC1=1&2 JC2=1&2 JC3=1&2 JC4=Open JC5=1&2
2RN16=Installed RN17/RN18/RN19=Not installed
3JCV1/JCV2=Jumper together pin 2 on JCV1 and pin 2 on JCV2 CN6=7&8&9&10

That are my current settings. It shows a 80487SX at 66mhz...

rxive wrote on 2024-06-20, 11:25:

dominusprog wrote on 2024-06-20, 11:18:

Try this […]
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Try this

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1JC1=1&2 JC2=1&2 JC3=1&2 JC4=Open JC5=1&2
2RN16=Installed RN17/RN18/RN19=Not installed
3JCV1/JCV2=Jumper together pin 2 on JCV1 and pin 2 on JCV2 CN6=7&8&9&10

That are my current settings. It shows a 80487SX at 66mhz...

That's the thing, this board doesn't support the Cyrix 5x86 processors. Try replacing the RN16 position with RN19.

dominusprog wrote on 2024-06-20, 11:29:

rxive wrote on 2024-06-20, 11:25:

dominusprog wrote on 2024-06-20, 11:18:

Try this […]
Show full quote

Try this

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1JC1=1&2 JC2=1&2 JC3=1&2 JC4=Open JC5=1&2
2RN16=Installed RN17/RN18/RN19=Not installed
3JCV1/JCV2=Jumper together pin 2 on JCV1 and pin 2 on JCV2 CN6=7&8&9&10

That are my current settings. It shows a 80487SX at 66mhz...

That's the thing, this board doesn't support the Cyrix 5x86 processors. Try replacing the RN16 position with RN19.

I mean it's listed everywhere as supported... Somebody must be running this combo somewhere.

https://dosdays.co.uk/topics/cpus.php

See under the Cyrix 5x86 section. It's on the known to support list, and it seems the list is very short.

Also here:
https://www.elhvb.com/supportbios.info/archiv … FIC/faqs486.htm

JCV1/JCV2 and CN6 are in the correct position, have you tired changing the RN16/RN19 position?

dominusprog wrote on 2024-06-20, 11:44:

JCV1/JCV2 and CN6 are in the correct position, have you tired changing the RN16/RN19 position?

I did. No change. But i found this...

https://www.dosdays.co.uk/topics/review_fic_4 … vip-io2_pt2.php

A different board but also a FIC. It seems that this is not really a problem, but only cosmetic. I think i'll try the 5.17 bios of a much later date, which might have this fixed.

Ok for anyone having the same problem, the latest 5.17 bios fixes the issue. It's now recognised correctly, with the RN19 installed it's recognised as 5x86 100MHz. The other settings are as dominusprog listed. 486-PVT supports Cyrix 5x86 PR100 as stated on other sites.

I don't know why the previous picture is just 8kb so i'm posting it again 😀

Glad it worked out, but you should increase the RAM to at least 16 MiB.

dominusprog wrote on 2024-06-20, 19:51:

Glad it worked out, but you should increase the RAM to at least 16 MiB.

I did that already. But now i have an external cache problem. As soon as i enable it, the machine hangs somewhere after the bios screen before the boot procedure starts. I tried a million bios settings, and it acts differently with different settings, i mean it hangs at different times. I'll have to check the sram cache chips. Any other ideas?

rxive wrote on 2024-07-01, 06:20:

dominusprog wrote on 2024-06-20, 19:51:

Glad it worked out, but you should increase the RAM to at least 16 MiB.

I did that already. But now i have an external cache problem. As soon as i enable it, the machine hangs somewhere after the bios screen before the boot procedure starts. I tried a million bios settings, and it acts differently with different settings, i mean it hangs at different times. I'll have to check the sram cache chips. Any other ideas?

Remove the cache chips carefully and use a contact cleaner on the sockets. Keep in mind that one of the chips is a TAG.

dominusprog wrote on 2024-07-01, 12:29:

rxive wrote on 2024-07-01, 06:20:

dominusprog wrote on 2024-06-20, 19:51:

Glad it worked out, but you should increase the RAM to at least 16 MiB.

I did that already. But now i have an external cache problem. As soon as i enable it, the machine hangs somewhere after the bios screen before the boot procedure starts. I tried a million bios settings, and it acts differently with different settings, i mean it hangs at different times. I'll have to check the sram cache chips. Any other ideas?

Remove the cache chips carefully and use a contact cleaner on the sockets. Keep in mind that one of the chips is a TAG.

Well that was it... I took out the chips, tested them in an eprom programmer (all ok), reseated and it works. It seems like it was a corrosion problem. Thanks for the tips.

rxive wrote on 2024-07-01, 18:54:

dominusprog wrote on 2024-07-01, 12:29:

rxive wrote on 2024-07-01, 06:20:

I did that already. But now i have an external cache problem. As soon as i enable it, the machine hangs somewhere after the bios screen before the boot procedure starts. I tried a million bios settings, and it acts differently with different settings, i mean it hangs at different times. I'll have to check the sram cache chips. Any other ideas?

Remove the cache chips carefully and use a contact cleaner on the sockets. Keep in mind that one of the chips is a TAG.

Well that was it... I took out the chips, tested them in an eprom programmer (all ok), reseated and it works. It seems like it was a corrosion problem. Thanks for the tips.

You're welcome 👍🏻