There is an option in BIOS to set BUS speed, i tried all the settings, but it didn't help???? If there is something els i could try?
Thanks

The bus speed settings are typically locked to the FSB for cpu (on 286,386,486), at 33Mhz the VLB should be 33Mhz, The ISA should be FSB/4 or about 8.3Mhz which is fine. Double check the BIOS and post a picture of the BUS speed part please.
The jumpers for VLB for wait state and >33mhz typically just add wait states/delays but only for the VLB slot portion.
Also: Can you post a picture of the 8bit VGA card that works and one of the 16bit VGA cards you tried that did not ?

Horun wrote on 2024-10-06, 20:05:

The bus speed settings are typically locked to the FSB for cpu (on 286,386,486), at 33Mhz the VLB should be 33Mhz, The ISA should be FSB/4 or about 8.3Mhz which is fine. Double check the BIOS and post a picture of the BUS speed part please.
The jumpers for VLB for wait state and >33mhz typically just add wait states/delays but only for the VLB slot portion.
Also: Can you post a picture of the 8bit VGA card that works and one of the 16bit VGA cards you tried that did not ?

Here are the pics....
CLKIN options can be set from /2 to /8, or automatic is 7.16MHz.
Those are the cards, smaller one that works, and VLB that works on other 486 MBOs, and it beeps on this one 🙁
Thanks a lot

butjer1010 wrote on 2024-10-05, 11:57:

I didn't ask one question! If i connect 8bit ISA Graphics Card into "first part" of 16bit ISA slot, will it work? I'm asking because, when i connect that only working 8bit ISA card into those other slots (16bit and VLB), it beeps like those other cards?!?

Yeah it should.

myne wrote on 2024-10-07, 11:57:

butjer1010 wrote on 2024-10-05, 11:57:

I didn't ask one question! If i connect 8bit ISA Graphics Card into "first part" of 16bit ISA slot, will it work? I'm asking because, when i connect that only working 8bit ISA card into those other slots (16bit and VLB), it beeps like those other cards?!?

Yeah it should.

Then the problem is in ISA slots!?! It works only in first, 8-bit slot.

I assume so

Is there any way to check it without oscillator?

You've tried all of them?

myne wrote on 2024-10-07, 14:26:

You've tried all of them?

Yes i did 🙁 No luck

Maybe one thing I need to add, don't know if that can tell anything - When i insert both cards into their slots, i get normal POST beep (one), but there is no video output on either card. If only VLB is inserted there is 1 long and 3 short beeps....

Got a multimeter and patience?

First, check voltages on the 8 bit portion of the slots that don't work.

If that all seems fine, trace out the 8 bit data portion of the slots.

We're looking for something that would stop the 8bit video card working.

If you find something, it can be fixed. Then, most likely the vlb cards will work again.

But if not, and the 8 bit card now works, it's time to verify the 16bit. Then the vlb.

Yes i have. So far i have checked only the voltages on all slots, and they were ok. 5, -5, 12, -12, all ok. So You are suggesting to try all data lines, from first that work to the last on the board?
Thanks

Finally i have found time to deal with this board!!!! As some of You were suggesting, i tried to test connections between 8bit isa (working one) and 16bit isa slots (faulty)! Of course there was the problem - A1 and A2 didn't have continuity between first 8 bit isa slot and other 16bit and vlb slots!!! From the lower side of board i have solder 2 wires and everything is working now!!!!!! AAAAAAAAAAAAAAAAAA, thanks to everyone, i'm so happy now! Another Abit MBO is saved from Hell 😀

Good work !

👍