wackoreese wrote on 2020-08-13, 01:26:

I recently tried to install windows 95 on a HOT-555A motherboard with a pentium mmx cpu. Installation goes fine without any issues, aside from it refuses to make a boot disk. When I go to try and start it after install it goes from the windows 95 splash for several seconds and just immediately reboots. Safe mode works fine, but obviously it never officially finishes setup so there's many missing drivers. Enabling bootlog is useless as the last line is alwyas LoadSuccess=C:\WINDOWS\SETVER.EXE. In safe mode everything loads without issue and I even installed the drivers for my imagine vga card to see if that was a potential issue. Instead it still gets stuck in the same bootloop. What could be causing this issue?

My goto first test in case of weird stability/reboot issues is Memtest .

I've got the same motherboard, and have the same issue, except with Windows 98, it will try to boot with the PMMX (mine is a SL27S/233MMX) before getting stuck into an infinite SCANREG loop.

I'm fairly sure that there's something going on with the board, I have not been able to find what was causing the issue however I tried cooling down the VRMs, flexing the board slightly, tried even a IDE and SCSI HDD, no dice.

I tried also a Memtest, but it instantly froze solid. Even with SDRAM and regular EDO SIMMs (since the 555A can take either SDRAM or EDO).

I'm thinking that I might have gotten a dodgy SL27S, though without another motherboard it's really difficult to know.

Vynix wrote on 2020-08-13, 01:47:

I've got the same motherboard, and have the same issue, except with Windows 98, it will try to boot with the PMMX (mine is a SL2 […]
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I've got the same motherboard, and have the same issue, except with Windows 98, it will try to boot with the PMMX (mine is a SL27S/233MMX) before getting stuck into an infinite SCANREG loop.

I'm fairly sure that there's something going on with the board, I have not been able to find what was causing the issue however I tried cooling down the VRMs, flexing the board slightly, tried even a IDE and SCSI HDD, no dice.

I tried also a Memtest, but it instantly froze solid. Even with SDRAM and regular EDO SIMMs (since the 555A can take either SDRAM or EDO).

I'm thinking that I might have gotten a dodgy SL27S, though without another motherboard it's really difficult to know.

I do know my board flexes a tad when I insert the vga card, but it's very miniscule. The back ports for the expansions cards somehow got knocked up a bit and this ends up as a result.

I don't think it has to do with a bad contact on the board (as I said I tried bending my board a little bit, though not much in fear of breaking it, with how scarcer and scarcer Socket 7 boards are getting, I'd rather not risk my only working board). My board doesn't flex at all if I insert a PCI or ISA card

I initially thought that it was a voltage issue, since the SL27S expects 2.8V and the lowest the 555A goes is 2.9V, though some people said that it's within spec and should work..

I tried Memtesting with SDRAM and EDO (my only SDRAM sticks are all bad and the EDO ones test fine) with the P133, tomorrow I will attempt the same with the 233MMX.

What about a BIOS Update?

https://downloads.zdnet.de/31514/shuttle-hot-555a-97154/

I'll try to update the BIOS real soon. NT 4.0 installed and runs no problem which is really confusing to me as to why 95 just loops.

I once built a system that would reboot itself after a random interval (but usually less than 30 minutes). After trying everything software-wise I went back to the minimum equipment (motherboard, video card, FDD controller), and still had the problem. It turned out that I had used a screw mount for the motherboard instead of a plastic standoff somewhere that made intermittent contact with a trace on the motherboard (probably as the system heated up) - found it by pressing down on the motherboard and voila, instant reboot.