The v1.3 board has the exact same chipset and seems to be mostly identical. You might get away with that bios file. To me it would be worth a chance 😀

Hello and thank you for your reply! DataExpert EXP4407 VER 1.3 has UNIchip U4800-VLX with part number UB03-1967 and DataExpert EXP4407 VER 1.1 has UNIchip U4800-VLX chiplset with part number 4l04f-1914. Is there a problem? My motherboard (1.1) posts with both BIOS by stuck at "wait.... " after memory counting. My diagnostic card shows error "80" which means keyboard check for stuck keys and problems but keyboard (according to manual) shows no signs of life except the power on when I the three leds are flashing for a second. Any ideas what is the problem???

Any ideas for the wait....problem??? Could it be problem with cache memory?

keeper5511 wrote on 2025-09-08, 16:50:

Any ideas for the wait....problem??? Could it be problem with cache memory?

Hi keeper5511,

Another interesting 486 board you have there!
Did you try the EXP4407 Ver 2.0 Award BIOS? I believe this 11/03/93-UNICHIP-U4800VL-2C460D00-00 BIOS will work on earlier EXP4407 versions as well.

Note that a few weeks ago I sent a correct ROM copy of this Award BIOS to TheRetroWeb, because the previous download was a Shadow RAM copy and had checksum errors. So if you downloaded this BIOS before, please download it again to get a correct copy.

Cheers, Jan

Glad to see you again my friend!

This task seems to be a little more difficult since we have post and at the first sceen loading stops at wait....
I have trying different simm ram and BIOSes from all unichip 4404 1.x (1.0 1.1 & 1.3) without success. I will try unichip 2.0 revision bios despite the fact that this edition seems a bit different from mine (can take 72pin RAM etc).

Is there a possibility that cache chips may be responsible for "wait..." stuck error????

keeper5511 wrote on 2025-09-14, 09:13:

Glad to see you again my friend! […]
Show full quote

Glad to see you again my friend!

This task seems to be a little more difficult since we have post and at the first sceen loading stops at wait....
I have trying different simm ram and BIOSes from all unichip 4404 1.x (1.0 1.1 & 1.3) without success. I will try unichip 2.0 revision bios despite the fact that this edition seems a bit different from mine (can take 72pin RAM etc).

Is there a possibility that cache chips may be responsible for "wait..." stuck error????

This hang at “wait….” can be caused by a number of different problems, including L2 cache issues.

I’m more familiar with the Award BIOS, so if you can install the EXP4407 Ver 2.0 Award BIOS and look at the POST analyzer card for the code where it hangs, I should be able to tell you more.

Jan

Hello again! Before flashing the BIOS I noticed 2 broken traces from the battery side!!!

Both are coming near KB connector (upper side) and following the traces from the bottom side of motherboard seems to get close to cache chips). Traces From the other side goes 1) to a chip SN54F244N (OCTAL BUFFERS/DRIVERS WITH 3-STATE OUTPUTS) and the second is unclear if ti goes to ext battery connector!!!

Motherboard stops at 80 post code while screen stays at "wait..."with current BIOS. I think its better to proceed with fixing those traces before attempt any further troubleshooting....

keeper5511 wrote on 2025-09-18, 19:05:

Hello again! Before flashing the BIOS I noticed 2 broken traces from the battery side!!!

Both are coming near KB connector (upper side) and following the traces from the bottom side of motherboard seems to get close to cache chips). Traces From the other side goes 1) to a chip SN54F244N (OCTAL BUFFERS/DRIVERS WITH 3-STATE OUTPUTS) and the second is unclear if ti goes to ext battery connector!!!

Motherboard stops at 80 post code while screen stays at "wait..."with current BIOS. I think its better to proceed with fixing those traces before attempt any further troubleshooting....

Good that you found these broken traces!
Because they are near the KB connector, this most probably is the cause of the error symptoms you described.

When the board comes back to life after fixing these traces, you may not even need a BIOS update. But you can always experiment with which BIOS works best for you. If you do the update, I would be curious about the Award BIOS and if it works on your PCB 1.1 board.

Cheers, Jan