Hi, as i see on picture, oscillator is 66MHz, and CPU is 25? Mabybe this CPU can't go 33MHz?

I would say the same.. The board is for 33mhz cpus.

1) change the cpu to 33mhz
2) use only two sticks of ram on bank0. no need to 4 for now, and you can test the ram sticks
3) do you have a POST card to see if the board gives some codes, or dont initialize ? its a very big difference.

Since it is a 386DX, it is correct to use 4 SIMM 30 PIN, 2 instead are fine on the 386SX.
The CPU could probably work at 33 MHz, but it's better to try a 386DX-33 instead of that 386DX-25.

Thanks guys for suggestions. Unfortunately I do not have 33MHz processor, last one was sold on Aukro in one auction in 2023. I will take a look somewhere else. Nuno, I don't see anything on screen so I can't tell. Is it possible that I burned my 25MHz when the oscillator runs higher?

No. It does not burn.
PS.Nice server/workstation board. Never seen a 386 with so many SIMM. Like whoa 16x4MB 64MB for a 386.

Nice Rabbit.

Based on the older style cache chips it uses, I'm going to say you probably have an older revision chipset that only supports 64kb cache and 16MB...no 4MB SIMM support.

Possibly need 4x 9-chip RAM SIMMs to get it to post.

Some boards like this might also use a Fujitsu type keyboard controller which is slightly different.

Sorry, I read it wrong before. Unfortunately I don't have POST card, would be good to have one.

nuno14272 wrote on 2025-11-03, 09:38:

I would say the same.. The board is for 33mhz cpus. […]
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I would say the same.. The board is for 33mhz cpus.

1) change the cpu to 33mhz
2) use only two sticks of ram on bank0. no need to 4 for now, and you can test the ram sticks
3) do you have a POST card to see if the board gives some codes, or dont initialize ? its a very big difference.

Yes it is a nice piece, glad I got something unusual like this.

Cyberdyne wrote on 2025-11-03, 10:38:

No. It does not burn.
PS.Nice server/workstation board. Never seen a 386 with so many SIMM. Like whoa 16x4MB 64MB for a 386.

So now I will need i386 33MHz processor, 4pcs of 9chip simm modules and Fujitsu controller...challenge accepted. Shame I did not wait for these suggestions although I wouldn't be able to now that someone will post here these info, because this morning I ordered keyboard bioses and one for my another 486 system. If I had waited bit longer I would have ordered those Fujitsu as well 😀. I really appreciate it.

MikeSG wrote on 2025-11-03, 15:20:

Possibly need 4x 9-chip RAM SIMMs to get it to post.

Some boards like this might also use a Fujitsu type keyboard controller which is slightly different.

I saw that you have in the photo, a 50.0 MHz OSC4, if that's what he uses for the CPU, that 386DX25 is fine.
But is the one in the photo your motherboard, or is it the same as yours?

Not exactly sure what do you mean, but this mobo has 66MHz oscillator as you can see above memory modules.

Gavrilo wrote on 2025-11-03, 19:28:

Not exactly sure what do you mean, but this mobo has 66MHz oscillator as you can see above memory modules.

Next to the 66 MHz one is the 50 MHz one, the visual aspect is different, but it is possible that this (50) is the one for the CPU frequency, I don't know what that 66 is for.

Oh I see, you're right, there is another one next to that 66MHz. So now I am confused. Maybe others will be able to shed some light on it? Because now we have here two oscillators.

I also didn't saw this other oscillator 🙁
So, if You turn it on without SIMs, and with speaker connected, there is no sound at all?

I mena... every jumper is hardwired already.. so is dificult to understand whats fsb is running.

I have the impression that the pins in SIS chip, the one close to RAM, are bent. Please check carefully whether there is no short circuit between some of these, or that some pin has lost contact with pcb.

Gavrilo wrote on 2025-11-03, 18:15:

So now I will need i386 33MHz processor, 4pcs of 9chip simm modules and Fujitsu controller...challenge accepted. Shame I did not wait for these suggestions although I wouldn't be able to now that someone will post here these info, because this morning I ordered keyboard bioses and one for my another 486 system. If I had waited bit longer I would have ordered those Fujitsu as well 😀. I really appreciate it.

MikeSG wrote on 2025-11-03, 15:20:

Possibly need 4x 9-chip RAM SIMMs to get it to post.

Some boards like this might also use a Fujitsu type keyboard controller which is slightly different.

99% likely needs the 9-chip SIMMS. I think the keyboard controller is fine... The hex inverter is sometimes different (7404/7405/7406/7407), but the one you have looks like it's for the AMI controller, which is what you already have.

zami555 wrote on Yesterday, 13:13:

I have the impression that the pins in SIS chip, the one close to RAM, are bent. Please check carefully whether there is no short circuit between some of these, or that some pin has lost contact with pcb.

The attachment IMG_20251104_140623.jpg is no longer available

Good eye You have 😉