I ruled out keyboard issues because when executing ECHO G=FFFF:0000 | DEBUG it also hangs with the blinking cursor

Update: I removed all PCI and ISA cards, but same result

Tried other graphics cards:

• Gf4 4200 AGP: same result
• Gf3-500 AGP: PC doesnt boot at all
• Gf2 Ultra AGP: same result
• Riva128ZX PCI: hangs after soft reset with garble graphics
  The attachment softreset3.jpg is no longer available
• Riva128 PCI: PC doesnt boot at all
• MGA-1064SG PCI: PC doesnt boot at all
• ET4000AX ISA: hangs at cursor but also PC speaker has one lasting tone that never stops

In general, whenever you see graphics corruption from a PCI graphics card that's known working fine in another system and not known to be a failure-prone GPU (e.g. some VooDoo GPUs), then the issue is more than likely data corruption related to the Southbridge.

Given that both PCI and ISA devices (GPUs) seem to be having issues on your system, it looks like there's some data corruption associated with the Southbridge. Could be a multitude of reasons for this: a failed/failing Southbridge (very unlikely) or possibly one with bad solder connections on the pins, or bad caps on the mobo or inside the PSU. If any component is running over-clocked, that can also be part or entirely the problem.
More details about the hardware would help. In some cases, pictures can also be useful to post.

I bought a post card and after 8 tries I got 8 different error codes when it's hanging.
The post card seems to be fine though because it shows proper codes after hard reset (e.g. during ram check).
It seems to be random whether or not I get PC speaker continous beep after it's haning (3 out of 8 )

... only 5 pics per post

momaka wrote on 2025-07-18, 00:43:

In general, whenever you see graphics corruption from a PCI graphics card that's known working fine in another system and not known to be a failure-prone GPU (e.g. some VooDoo GPUs), then the issue is more than likely data corruption related to the Southbridge.

Given that both PCI and ISA devices (GPUs) seem to be having issues on your system, it looks like there's some data corruption associated with the Southbridge. Could be a multitude of reasons for this: a failed/failing Southbridge (very unlikely) or possibly one with bad solder connections on the pins, or bad caps on the mobo or inside the PSU. If any component is running over-clocked, that can also be part or entirely the problem.
More details about the hardware would help. In some cases, pictures can also be useful to post.

I'm sorry I have overlooked your post.

Hardware is K6-3+/400 with DFI K6XV3/66 Rev B1
No overclocking

I changed PSUs so I don't think it's the PSU.
I tested the processor on a DFI K6XV3 Rev A board which doesnt have this problem, I don't think it's the CPU

I solved the problem by flashing the latest beta bios. Funny isn't it