MB-8433UUD Bad BIOS? \ VOGONS

MB-8433UUD Bad BIOS?

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First post, by therelaxer

Posted on 2023-10-11, 22:53

therelaxer Offline

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Location: OK, USA

I have had this motherboard for a long time. I did have it working at some point well over a decade ago. I pulled it out and I cannot get it to post. I remember having it working. When it is powered on no components are hot or seem like they are having a problem.

No matter what ram; FPM, EDO, 2MB to 64MB sticks; or which CPU; AMD DX4 100 NV8T, SV8B or Intel DX 33. I even tried booting it with the power supply from my IBM 5170 thinking it may require -5v. No dice.

Other than buying some EEPROMS and a programmer IDK what else to try. It sure looks like a dead BIOS. Perhaps I did the no-no and attempted this: "Attempting to flash a UV-erasable BIOS in the motherboard will ruin the BIOS chip". The current CMOS chip does have the window. I can see its outline underneath the sticker.

The only things I do remember doing to this board was to solder in a dip socket for the RTC. Though I think I am going to buy one of those new fancy ones that takes the CR2032 AFTER I get it posting again. I have a beeper or speaker on the way to hook up to it to see if it has a beep code or anything. Please forgive the ISA videocard, I have a diamond stealth 64 on the way.

I have added some photos below of the board.

Any ideas? EEPROM and programmer time?

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Reply 1 of 7, by Repo Man11

Posted on 2023-10-12, 01:28

Repo Man11 Offline

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There are motherboards that will not POST if the CMOS/RTC battery is dead.

"I'd rather be rich than stupid" - Jack Handey

Reply 2 of 7, by therelaxer

Posted on 2023-10-12, 01:55

therelaxer Offline

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Repo Man11 wrote on 2023-10-12, 01:28:

There are motherboards that will not POST if the CMOS/RTC battery is dead.

On that note, I have one of those dallas replacement modules that takes the coin cell batteries on the way now. Thanks Repo Mann11.

Reply 3 of 7, by Nexxen

Posted on 2023-10-12, 01:57

Nexxen Offline

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There are Dallas hack guide on YT, if needed.

BIOS probably, but have you checked traces of the socket you put in?
A good wash could be a good thing, + deox all the contacts
Deox first.

Try removing all the L2 cache and set it to 0KB.

To start.

PC#1 Pentium 233 MMX - 98SE
PC#2 PIII-1Ghz - 98SE/W2K

Reply 4 of 7, by therelaxer

Posted on 2023-10-12, 02:13

therelaxer Offline

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Location: OK, USA

Nexxen wrote on 2023-10-12, 01:57:
There are Dallas hack guide on YT, if needed. […]
Show full quote

There are Dallas hack guide on YT, if needed.

BIOS probably, but have you checked traces of the socket you put in?
A good wash could be a good thing, + deox all the contacts
Deox first.

Try removing all the L2 cache and set it to 0KB.

To start.

Traces look good on both sides of the socket. I do remember that with the replacement dallas chip that it was saving settings. Do you agree if the battery is dead it may not post? I will try the deox and removing all the L2 and the TAG tomorrow. Thanks

Reply 5 of 7, by Nexxen

Posted on 2023-10-12, 02:50

Nexxen Offline

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Location: Italy

therelaxer wrote on 2023-10-12, 02:13:

Nexxen wrote on 2023-10-12, 01:57:
There are Dallas hack guide on YT, if needed. […]
Show full quote

There are Dallas hack guide on YT, if needed.

BIOS probably, but have you checked traces of the socket you put in?
A good wash could be a good thing, + deox all the contacts
Deox first.

Try removing all the L2 cache and set it to 0KB.

To start.

Traces look good on both sides of the socket. I do remember that with the replacement dallas chip that it was saving settings. Do you agree if the battery is dead it may not post? I will try the deox and removing all the L2 and the TAG tomorrow. Thanks

Yes, some do not post. It's rare though, usually you get a cmos battery error.

PC#1 Pentium 233 MMX - 98SE
PC#2 PIII-1Ghz - 98SE/W2K

Reply 6 of 7, by Repo Man11

Posted on 2023-10-12, 03:12

Repo Man11 Offline

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Posts: 1855
Joined: 2013-04-23, 01:56
Location: California

Here's a recent example - Necroware also had a video on this issue. Rescue Socket 7 PC with weird CPU and motherboard combo -- advice needed

"I'd rather be rich than stupid" - Jack Handey

Reply 7 of 7, by bloodem

Posted on 2023-10-12, 03:42

bloodem Offline

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Location: Romania

Repo Man11 wrote on 2023-10-12, 01:28:

There are motherboards that will not POST if the CMOS/RTC battery is dead.

The 8433UUD is not one of those boards, though (I have three of these).
It does POST just fine with a dead RTC battery, however you won’t be able to boot into any OS (because it forgets the IDE settings).

1 x PLCC-68 / 2 x PGA132 / 5 x Skt 3 / 9 x Skt 7 / 12 x SS7 / 1 x Skt 8 / 14 x Slot 1 / 5 x Slot A
5 x Skt 370 / 8 x Skt A / 2 x Skt 478 / 2 x Skt 754 / 3 x Skt 939 / 7 x LGA775 / 1 x LGA1155
Current PC: Ryzen 7 5800X3D
Backup PC: Core i7 7700k

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