VOGONS


First post, by Cyrix200+

User metadata
Rank Oldbie
Rank
Oldbie

I have a motherboard that looks a lot like an Abit AV4 (http://www.uncreativelabs.de/th99/m/S-T/35060.htm).

The board does not POST, does not beep and gives no POST codes .

I have attached the image of the BIOS that came with the board, and I think it might be the wrong BIOS.

Does anyone have an Abit AV4 BIOS image I could try?

IMG_20200326_172321.jpg
Filename
IMG_20200326_172321.jpg
File size
1.93 MiB
Views
209 views
File license
Public domain

Attachments

Reply 1 of 13, by Horun

User metadata
Rank Oldbie
Rank
Oldbie

The bios ID string in your file is 40-0101-001133-00101111-111192-SIS461. the 1133 relates to Micro Leader Enterprises. According to Wims BIOS it should be 1247 for Abit.
It is possible it is the right bios as Abit did have some boards made by other manufactures, specially the older ones. There is no identifiers on the board itself that show the Abit logo.
Unfortunately I cannot find a BIOS for the AV4, just the AH4 and AN4R2. Maybe someone else will have better luck,

First computer was an IBM 3270 workstation with CGA monitor. 🤣

Reply 2 of 13, by Cyrix200+

User metadata
Rank Oldbie
Rank
Oldbie
Horun wrote on 2020-03-26, 17:40:

The bios ID string in your file is 40-0101-001133-00101111-111192-SIS461. the 1133 relates to Micro Leader Enterprises. According to Wims BIOS it should be 1247 for Abit.
It is possible it is the right bios as Abit did have some boards made by other manufactures, specially the older ones. There is no identifiers on the board itself that show the Abit logo.
Unfortunately I cannot find a BIOS for the AV4, just the AH4 and AN4R2. Maybe someone else will have better luck,

Yeah, I found the same info. All I have to prove this is a AV4 is the information from TH99 (and they might be wrong).

I found a POST screen picture here: http://pcrebuilding.altervista.org/49/57/2nd+ … +Lightning.html

The BIOS string there is 40-00AG-001247-00101111-060692-SIS3486-F .

Where did you find the AH4 and AN4R2 BIOS images? I might try those, the boards are quite similar.

Thanks for your time 😀

Reply 3 of 13, by PC Hoarder Patrol

User metadata
Rank Oldbie
Rank
Oldbie

Did you notice that the board in the PC Rebuilding link uses the SiS460 rather than the 461 chipset, and there are differences in some of the IC / socket layouts as well. Your board looks more like this one

https://translate.google.com/translate?hl=en& … 687&prev=search

Reply 4 of 13, by Horun

User metadata
Rank Oldbie
Rank
Oldbie

I do not think the AN4R2 bios will work: "Award Software Inc. 08/30/95-SIS-85C471E/G-2C4I9A12-02"
Different SIS chipset. https://soggi.org/motherboards/abit.htm#S486
And if you use the wayback machine: https://web.archive.org/web/19971221083125/ht … ml/download.htm
shows AH402.EXE for the AH4 and AN4R2 which would be ah4_02.bin as here: ftp://retronn.de/mirrors/ftp.abit.com/pub/dow … d/fae/ah402.exe

First computer was an IBM 3270 workstation with CGA monitor. 🤣

Reply 5 of 13, by AmiSapphire

User metadata
Rank Newbie
Rank
Newbie

Was taking a long break from doing some PCB work in KiCAD and saw this thread. I did find a ROM like that, but it had to be dug up from an old MAME 0.209-0.210 ROM update collection.

Found using hex editor:
40-00AG-001247-00101111-060692-SIS3486
AV4 ISA/VL-BUS SYSTEM BIOS

Attachments

  • Filename
    at486.zip
    File size
    40.2 KiB
    Downloads
    3 downloads
    File license
    Public domain

Computer in my collection that had too much work done is... Compaq Armada 1573DM!

- Original DSTN panel replaced with an HPA panel
- Left hinge repaired twice
- Front panel replaced twice
- Replaced busted inverter
- Chassis replacement

Reply 6 of 13, by Horun

User metadata
Rank Oldbie
Rank
Oldbie
AmiSapphire wrote on 2020-03-27, 01:28:
Was taking a long break from doing some PCB work in KiCAD and saw this thread. I did find a ROM like that, but it had to be dug […]
Show full quote

Was taking a long break from doing some PCB work in KiCAD and saw this thread. I did find a ROM like that, but it had to be dug up from an old MAME 0.209-0.210 ROM update collection.

Found using hex editor:
40-00AG-001247-00101111-060692-SIS3486
AV4 ISA/VL-BUS SYSTEM BIOS

Good job !

First computer was an IBM 3270 workstation with CGA monitor. 🤣

Reply 8 of 13, by H3nrik V!

User metadata
Rank Member
Rank
Member

Would the lack of a BIOS battery prevent it from powering up?
By the way, I see some green residue at where the battery has been. Are all traces intact?

Reply 9 of 13, by Cyrix200+

User metadata
Rank Oldbie
Rank
Oldbie
H3nrik V! wrote on 2020-03-27, 06:39:

Would the lack of a BIOS battery prevent it from powering up?
By the way, I see some green residue at where the battery has been. Are all traces intact?

All traces look fine (visually), and I have checked continuity and I cannot find anything wrong. I tried powering on with an external battery pack.

The PSU spins up and keeps spinning, but there is no further activity. No POST code on the POST card, no beeps.

Another thing I can check is the tantalums for shorts, although I would expect that the PSU would shut down with a short. Not all tantalums near the PSU connectors are the same, maybe somebody already replaced some? It wasn't me.

Reply 10 of 13, by Cyrix200+

User metadata
Rank Oldbie
Rank
Oldbie

Since I worked from home today I could do some tinkering.

- Changing the BIOS does not matter
- I thoroughly checked all connections where any acid damage was visible. I de-soldered the keyboard connector to check underneath. Everything had continuity. Two vias are nasty though, they do connect from top to bottom. I let them soak in vinegar for a while and cleaned them off again. No change
- Removed all cache chips, no change
- I notice on my POST card the reset line stays high. Not unexpected I think?
- When I press the reset button and hold it, the PSU fan slows down a bit
- Voltages on CPU socket and ISA slots seem fine. 5V is 4.8V, but I think that should be acceptable.

Any thoughts?

Reply 11 of 13, by Horun

User metadata
Rank Oldbie
Rank
Oldbie

Have you checked for shorts? Pull cpu and ram, make sure it a bare board other than cache. Use a good DVM and check resistance from all AT PSU connections to ground using proper polarity (ground being black lead 🤣). If any are less than 10Kohm make a note which ones. Is common for the +5v to be 500-2kohm. Next is the cache, have had boards fail to boot or give any sign of life with bad cache or bad memory. This is trickier so start with the possible shorts...

First computer was an IBM 3270 workstation with CGA monitor. 🤣

Reply 12 of 13, by Cyrix200+

User metadata
Rank Oldbie
Rank
Oldbie
Horun wrote on 2020-03-28, 01:37:

Have you checked for shorts? Pull cpu and ram, make sure it a bare board other than cache. Use a good DVM and check resistance from all AT PSU connections to ground using proper polarity (ground being black lead 🤣). If any are less than 10Kohm make a note which ones. Is common for the +5v to be 500-2kohm. Next is the cache, have had boards fail to boot or give any sign of life with bad cache or bad memory. This is trickier so start with the possible shorts...

Okay, had a spare moment. DVM set to auto range. Bord was empty (no CPU or RAM), since cache was already out I kept it out. Power good and +12V are suspicious I think? Another board did give results on those also.

P8
1: Power good: Out of limits
2: -5V: 1Kohm
3: +12V: Out of limits
4: -12V: 12Mohm
5: 0
6: 0

P9
1: 0
2: 0
3: -5V: 13Mohm
4: +5V: 1Kohm
5: +5V: 1Kohm
5: +5V: 1Kohm

Reply 13 of 13, by Horun

User metadata
Rank Oldbie
Rank
Oldbie

Those all look ok but maybe the PG and +12v as you said. The Power Good usually sits 3M-10Mohm but is board dependent. You can check it with the PSU connected and turned on (with CPU in) and see if it comes to near +5v after a second or two. The +12v should be close to the -12v in Mega ohms too. Luckily you have no shorts but maybe a possible open +12v circuit.

First computer was an IBM 3270 workstation with CGA monitor. 🤣