It has gemlight vibes to me, and a lot of their later 486 and pentium boards are very poorly documented and models missing. Something between the
https://theretroweb.com/motherboards/s/gemlig … t-cobra-xlp-pci
and
https://theretroweb.com/motherboards/s/gemlight-cobra-xlt
maybe or a parallel undoc cobra model.

jaquamala wrote on 2022-12-03, 21:53:

I think that the main problem is an defect bios chip. The bios chip is an MX28F1000PD. With my TL866II (Xgpro know the model MX28F1000P without an D on the end) can´t read out the chip. It appears fault is a wrong ID.

in XGpro disable 'Check ID'
Reading out an eeprom shouldn't be a problem. Programming it might.

This link - ftp://retronn.de/driver/Mainboards/Award_BIOS … otherboard.html - lists an SiS 5501/02/03 Chipset (Pentium based m/b); the Mirage M54PS, with a bios string of 2A5ICAM1 which points to Achme as the maker

Wow good find. So it is most likely a MSI (oem?) board according to Achme's old website....

Given how spartan this board is - literally just 5501 chipset and nothing else - the BIOS from another similar 5501 board might well work on it. Only problem is that all other 5501 boards I can find have an additional I/O controller for floppy, serial and parallel. One of their BIOS might work, but no guarantees.

Oh wow that it beautiful. Good find.

On the off chance that the bios is a red herring,
Try fpm ram and a pentium 200 non mmx, and a different video card. I had the same problem on another socket 5 ended up solving it. Fingers crossed I also for a time suspected the bios. But it was fine.

If I were to guess, based on the silkscreen of just 75, 90 and 100Mhz (JP7-JP9 which would be 50Mhz, 60Mhz and 66Mhz) that JV1 is Vstd/VRE jumper. JX1 and JX2 are the multiplier jumpers.
The JP7-JP9 set appear correct for P75. If the cpu came with the motherboard then possible JX1 and Jx2 are correct. Looking at JX there are four possibles. 1.5x, 2x, 2.5x and 3x.
If not then try as Spere478 mentioned a P200 non-mmx and see what happens, do not change JP7-JP9.
Also if using a good Diag card be sure to try in both in various PCI and ISA slots, many PCI boards will not output in a ISA slot and some rare boards do not from PCI #1 (SL1).

Thank you at all to help me here on this board. I made some progress:

weedeewee wrote on 2022-12-03, 22:54:

jaquamala wrote on 2022-12-03, 21:53:

I think that the main problem is an defect bios chip. The bios chip is an MX28F1000PD. With my TL866II (Xgpro know the model MX28F1000P without an D on the end) can´t read out the chip. It appears fault is a wrong ID.

in XGpro disable 'Check ID'
Reading out an eeprom shouldn't be a problem. Programming it might.

Without the marker "Check ID" i could read the chip. Bios attached. Thank you for the tip.

With the tool MODBIN i could take a peak inside of the bios file. Here i can see some available bios options and also
the bios post string: 05/09/95-SiS-5501-5503-2A5ICAM1-00

PC Hoarder Patrol wrote on 2022-12-04, 00:13:

This link - ftp://retronn.de/driver/Mainboards/Award_BIOS … otherboard.html - lists an SiS 5501/02/03 Chipset (Pentium based m/b); the Mirage M54PS, with a bios string of 2A5ICAM1 which points to Achme as the maker

I found the same informations as you. 2A5ICAM1: Mirage M54PS
I have test a other cmos flash chip but no change. There is no different between
the original bios chip and the other. Than could mean that bios is is not the fault. For now.

Sphere478 wrote on 2022-12-04, 01:23:

Oh wow that it beautiful. Good find.

On the off chance that the bios is a red herring,
Try fpm ram and a pentium 200 non mmx, and a different video card. I had the same problem on another socket 5 ended up solving it. Fingers crossed I also for a time suspected the bios. But it was fine.

Unfortunately i don't have a P200 non mmx to my hands. This board came to my without a battery,
but the battery left here some mess on the board. I cleanded it with vinegar and ipa. Around them there are some corroded pads/pins.
Maybe here is the fault and i need here some investigation with the oscilloscope.

I found out that randomly every 2-3 times when i power on the board the analyzer card show "07 06" bios post code.
For the Award bios means the "07" after the manual from the analyzer card: -> Verifies CMOS is working correctly. Detects bad battery.
A test with the additional fdd controller make no difference.

Have you tried changing the JX1 and JX2 jumpers ? There are only 4 combinations. Are you using a heatsink ?

Watch the heat on that cpu. 😀

Horun wrote on 2022-12-05, 02:06:

Have you tried changing the JX1 and JX2 jumpers ? There are only 4 combinations. Are you using a heatsink ?

Yes i had tried all possible combinations. I tested also another P 75 Mhz cpu but no change. For this picture i don't used a heatsink but regular yes. I measured with the osci some standard clock signals on the chipset and i found somthing on the rtc clock quartz. Nomally it should runs an 32,768 KHz. I could measure here only 6,5 KHz. I will change the quartz. Hopefully this is the fault.