majestyk wrote on 2024-05-25, 18:57:

The ATC-1425B is my first Socket 3 mainboard to have this issue. After the initial POST screen when memory has been counted and […]
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The ATC-1425B is my first Socket 3 mainboard to have this issue. After the initial POST screen when memory has been counted and IDE / Floppy ports have been probed, right when the BIOS summary screen would appear, the monitor turns black and the system freezes.

ISA cards and ATI PCI cards are working fine. Changing the "PCI sync / async" jumper makes no difference.

There are also instabilities at tighter RAM / cache timings no matter what RAM sticks or cache chips I use.

Has anybody encountered similar problems with this board?

Hallo, I know it is a necroposting 😀 But I have just spent numerous hours on the same board with no avail. My board boots with no vga! Once any vga is inserted it crashes with a post code 6061. Black screen and that is all. For a while it was working with an ISA Trident 9000, but later on again not even with ISA. Your situation is better, but very similar...can wrap my head around it...Still trying.

majestyk wrote on 2024-05-25, 18:57:

The ATC-1425B is my first Socket 3 mainboard to have this issue. After the initial POST screen when memory has been counted and […]
Show full quote

The ATC-1425B is my first Socket 3 mainboard to have this issue. After the initial POST screen when memory has been counted and IDE / Floppy ports have been probed, right when the BIOS summary screen would appear, the monitor turns black and the system freezes.

ISA cards and ATI PCI cards are working fine. Changing the "PCI sync / async" jumper makes no difference.

There are also instabilities at tighter RAM / cache timings no matter what RAM sticks or cache chips I use.

Has anybody encountered similar problems with this board?

SOLVED
If any of you vogoneers hit this issue in the future on this board - try a different CPU. It seems there might be a bug in the jumper manual / or incompatibility. My CPU Am 486 DX4/100 T version - no WB cache was not working right. However once put a 486DX/33 Intel there the board worked just fine. So far no time to test with other CPU but the board is not faulty

H.W.Necromancer wrote on 2026-08-04, 22:02:

majestyk wrote on 2024-05-25, 18:57:

The ATC-1425B is my first Socket 3 mainboard to have this issue. After the initial POST screen when memory has been counted and […]
Show full quote

The ATC-1425B is my first Socket 3 mainboard to have this issue. After the initial POST screen when memory has been counted and IDE / Floppy ports have been probed, right when the BIOS summary screen would appear, the monitor turns black and the system freezes.

ISA cards and ATI PCI cards are working fine. Changing the "PCI sync / async" jumper makes no difference.

There are also instabilities at tighter RAM / cache timings no matter what RAM sticks or cache chips I use.

Has anybody encountered similar problems with this board?

SOLVED
If any of you vogoneers hit this issue in the future on this board - try a different CPU. It seems there might be a bug in the jumper manual / or incompatibility. My CPU Am 486 DX4/100 T version - no WB cache was not working right. However once put a 486DX/33 Intel there the board worked just fine. So far no time to test with other CPU but the board is not faulty

My first guess would be the cpu cache having an unexpected interaction with the vga rom. Is the video bios shadowed?

Second guess would be something related to the cpu voltage and the pci bus.

douglar wrote on 2026-08-08, 11:05:

Second guess would be something related to the cpu voltage and the pci bus.

That is really interesting point. It's worth to try another 3.3V CPU to check

zami555 wrote on 2026-08-08, 11:40:

douglar wrote on 2026-08-08, 11:05:

Second guess would be something related to the cpu voltage and the pci bus.

That is really interesting point. It's worth to try another 3.3V CPU to check

Maybe a dx4 or a 5x86 with a built in voltage regulator so the socket runs at 5v?

douglar wrote on 2026-08-08, 11:05:

H.W.Necromancer wrote on 2026-08-04, 22:02:

majestyk wrote on 2024-05-25, 18:57:

The ATC-1425B is my first Socket 3 mainboard to have this issue. After the initial POST screen when memory has been counted and […]
Show full quote

The ATC-1425B is my first Socket 3 mainboard to have this issue. After the initial POST screen when memory has been counted and IDE / Floppy ports have been probed, right when the BIOS summary screen would appear, the monitor turns black and the system freezes.

ISA cards and ATI PCI cards are working fine. Changing the "PCI sync / async" jumper makes no difference.

There are also instabilities at tighter RAM / cache timings no matter what RAM sticks or cache chips I use.

Has anybody encountered similar problems with this board?

SOLVED
If any of you vogoneers hit this issue in the future on this board - try a different CPU. It seems there might be a bug in the jumper manual / or incompatibility. My CPU Am 486 DX4/100 T version - no WB cache was not working right. However once put a 486DX/33 Intel there the board worked just fine. So far no time to test with other CPU but the board is not faulty

My first guess would be the cpu cache having an unexpected interaction with the vga rom. Is the video bios shadowed?

Second guess would be something related to the cpu voltage and the pci bus.

It did not matter if the video bios is shadowed or not. However the voltage theory need to be tested - do not know. So far no test with another 3.3V cpu