386 XCMOS checksum error but no extended setup option \ VOGONS

386 XCMOS checksum error but no extended setup option

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First post, by InbetweenDays

Posted on 2018-07-06, 09:25

InbetweenDays Offline

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I've got a 386SX-20 with the old school AMI BIOS. After replacing the dead external battery, it is giving an invalid XCMOS checksum error. Normally that's no problem - go into extended setup, write registers and exit...
However this BIOS has no extended setup option. The only menu options are exit for boot, run CMOS setup, and run diagnostics.

Any ideas on how I can fix this? I've cleared the CMOS but that didn't help. It seems some BIOSes didn't have the extended setup program, but then why give an XCMOS checksum error? 😕

Thanks,
Stu

It don't mean a thing if it ain't got 5-pin DIN.
Roland addict and founding member of the Association Of Molex Haters

Reply 1 of 4, by Predator99

Posted on 2018-07-06, 09:28

Predator99 Offline

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Does the BIOS keep the data you enter in the CMOS Setup?

Did the old battery cause damage when it leaked?

Is there a jumper for internal/external battery?

Reply 2 of 4, by InbetweenDays

Posted on 2018-07-06, 11:26

InbetweenDays Offline

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Yes, settings are retained just fine... there was no damage because it had an external battery fitted already (the motherboard is pristine and it doesn't look like there has ever been a battery soldered to it). No jumper for internal/external.

Anyway, an update... I found this page which describes the same issue being fixed by the setup386.com program required for C&T chipset boards. Unfortunately this doesn't seem to fix the problem because my C&T chipset differs... I have the 82C811/812/215/206 -- this would identify the most likely candidate to be the NeatSX board. I can't find my board on TULARC but the NeatSX is a very similar layout with the same chipset. Then I found this listing of utilities but the NeatSX link is dead 🙁

Last edited by InbetweenDays on 2018-07-06, 14:08. Edited 1 time in total.

It don't mean a thing if it ain't got 5-pin DIN.
Roland addict and founding member of the Association Of Molex Haters

Reply 3 of 4, by InbetweenDays

Posted on 2018-07-06, 14:07

InbetweenDays Offline

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Answering my own question... after some creative googling, I found this page which has the "C&T NEAT New Enhanced Chipset Extended CMOS Setup Utility 286, 386SX CS8281 - DOS" (Quickset utility for the NeatSX chipset).
Using that, I could configure the extended setup options such as RAM configuration, wait state etc... and voila, no more checksum error. 😀

It don't mean a thing if it ain't got 5-pin DIN.
Roland addict and founding member of the Association Of Molex Haters

Reply 4 of 4, by Jed118

Posted on 2020-02-25, 02:57

Jed118 Offline

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InbetweenDays wrote on 2018-07-06, 14:07:

Answering my own question... after some creative googling, I found this page which has the "C&T NEAT New Enhanced Chipset Extended CMOS Setup Utility 286, 386SX CS8281 - DOS" (Quickset utility for the NeatSX chipset).
Using that, I could configure the extended setup options such as RAM configuration, wait state etc... and voila, no more checksum error. 😀

Hah, you may have solved my issue with the Quickset utility that my NEAT-SX manual keeps referring to but never came with. 😁

*edit - yep, that worked! I was able to set the RAM interleave and wait states, the CPU speed (albeit I found a way to do that manually in XCMOS) and set the RAM speed. I got a bit of a performance boost on my benchmarks! 😁

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