Minimum hardware should just be CPU, RAM, Motherboard speaker and a VGA card. Try a simple 5V CPU like a DX33 if you have one.

Hell you probably don't need a video card if you have one of those POST display code cards.

Yes it should POST with a video card.
Is there any sign of life ? (error beeps, etc)
What happens if you remove the RAM stick, does it beep ?

Make sure your CPU is powered with 3.3V, it's a intel DX4, running it at 5V would kill it ...

You can find jumper settings over here http://www.win3x.org/uh19/motherboard/show/167
(feel free to send us a nice photo of your motherboard so we can add it 😁. Same deal with your BIOS if you get it to POST !)

Do you get beeps if the video card isn't installed?

You need a PC Speaker connected for beep codes of course.

Is the CMOS battery good?

I'm wondering what that Molex power connector suspiciously near the voltage regulator is for.
If you power it on does the cpu quickly get hot to the touch? Like within 10-15 seconds
If you indeed don't have a pc speaker connected, you don't know if it's not working at all or just beeping. Also, I've found when testing a VLB motherboard outside of the case, try wiggling the video card before you turn the power on as there is nothing to hold it firmly in place. You might also try the pencil eraser trick to clean the contacts on the video card.

If I remember correctly that is 5V only motherboard and you have put 3V cpu there. Also because of that the motherboard does not have jumpers to set cpu to dx4 ones. Perhaps you fried both of your dx4 cpus?

jakethompson1 wrote on 2020-10-08, 00:18:

I'm wondering what that Molex power connector suspiciously near the voltage regulator is for.
If you power it on does the cpu quickly get hot to the touch? Like within 10-15 seconds
If you indeed don't have a pc speaker connected, you don't know if it's not working at all or just beeping. Also, I've found when testing a VLB motherboard outside of the case, try wiggling the video card before you turn the power on as there is nothing to hold it firmly in place. You might also try the pencil eraser trick to clean the contacts on the video card.

According to the online diagram, that molex is for a case fan... But it is a female plug which indicates that it is for feeding power to the board.

Thank you everyone for your input. I unfortunately do not have a PC speaker to hook up to the board at the moment, so I am not able to tell if it beeps or not. I have some of the small PC speakers and an ISA diagnostics board coming in the mail this weekend. The CMOS battery is new. This board is capable of using 3V processors . There is a voltage regulator beside of the processor and the voltages are changed using the jumpers. I previously had one of these motherboards with a DX4 processor in it.

NC Mountain Man wrote on 2020-10-08, 20:27:

Thank you everyone for your input. I unfortunately do not have a PC speaker to hook up to the board at the moment

If you have an old pair of cheap (dollar tree type) headphones you can use one just strip the wires and solder a 4 pin header to either left or right side. Most of those cheap headphones are 32ohm and work very well as a cheap fix for a tester pc speaker....

NC Mountain Man wrote on 2020-10-08, 20:27:

Thank you everyone for your input. I unfortunately do not have a PC speaker to hook up to the board at the moment, so I am not able to tell if it beeps or not. I have some of the small PC speakers and an ISA diagnostics board coming in the mail this weekend. The CMOS battery is new. This board is capable of using 3V processors . There is a voltage regulator beside of the processor and the voltages are changed using the jumpers. I previously had one of these motherboards with a DX4 processor in it.

And you've already tried cleaning the ISA and VLB contacts on the graphics card, and bumping it back and forth to make sure it's securely in the slot?

Also to be on the safe side, make sure you use FPM SIMMs

That molex connector is used to plug in the CPU fan.

When you take a look at CPU fans from that era you'll notice that they have a male and a female molex connector. Normally you use the female connector to connect it to the PSU, but with this kind of motherboard you use the male connector instead. It's great for cable management 😁
And no it's not used to power the mobo. I guess it shouldn't hurt it if you try, but I wouldn't recommend trying that anyways

I received the POST code analyzer card today and it gives it gives a couple pieces of information. First it includes a speaker. When i hook the speaker up the motherboard, it does not make any beeps during the start up process. When looking at the numerical post codes, sometimes it will show that #13 fails and sometimes it will show that #5 fails. Post code #13 has to do with "Early POST initialization of chipset registers". When it fails at #5 there seems to be another problem. The post code card will go through the codes up until #5 and then restart itself, and then do that over and over. It is almost like the motherboard keeps restarting itself. Post code #5 has to do with "Initializes the interrupt controlling hardware (generally PIC) and interrupt vector table".

Try re-seating the BIOS chip? Any difference in the codes if you go with no RAM?