> "Test DMA Page Registers"
These kinds of tests are usually done while the screen is still black.

Maybe dirty connectors again?

I went a bit "mad", and inside the BIOS, set everything I could see to "disabled" - which was my way of setting the BIOS to "fail safe" mode. It now boots up OK. I have no idea why. Obviously one (or more) edited BIOS settings (set to disabled) have "done the trick", but it will take some more testing to see which disabled setting has cured the problem.

I've found the specific problem. If I set "external cache" to disabled, the mobo functions OK and boots up from a HDD. If I set "external cache" to enabled, then the mobo hangs during its POST operations, and cannot boot from a HDD. (The mobo gets to the point where it should mention "updating ESCD" but then hangs. Please note - it doesn't display anything about updating ESCD - it must hang just before this gets displayed on the screen.)

Also, the BIOS POST procedure displays "Cache 256k". I've checked the mobo jumpers, and I think they are set OK for 256k of cache.

Could one (or more) of the cache chips (or TAG chip) be defective? I'm using a 486 dx2 66 CPU with writeback cache - and the mobo displays this cpu as p24d-s

Thanks for any more help!! 😀

Solved! I changed the Intel 486 dx2-66 cpu for an AMD 486 dx4-100 cpu. That seemed to solve the L2 cache problem. Strange. Buggy mobo BIOS perhaps? I ran speedsys, just for a laugh. Also, Doom plays fast.

Finally, now I've changed the CPU, windows 98 crashes badly when it tries to display the desktop - Kernel error. Perhaps windows 98 is confused that I've changed the CPU?

Maybe the cache error manifests itself in a different way now that the CPU timing has changed... try to start Win98 without cache.

h-a-l-9000 wrote:

Maybe the cache error manifests itself in a different way now that the CPU timing has changed... try to start Win98 without cache.

I tried setting level 2 cache to disabled, and level 1 cache to write thru (not write back), but windows 98 has become very unstable. I think it may require reinstallation.

I decided not to reinstall windows 98, but instead to go back to the Intel 486 DX2-66 cpu. With L2 cache enabled, and L1 cache set to writeback, all is OK. I don't know why, but it works.

One other thing I noticed - Magic Carpet didn't like the AMD DX4 cpu. Hexen also crashed about 30 seconds playing the game with the AMD cpu.

The conclusion I have to come to is this - I don't know what I'm doing. 🤣

You took your time, I came to that conclusion ages ago 😁

Davros wrote:

You took your time, I came to that conclusion ages ago 😁

🤣 One reason I appear to be so stupid, is that I didn't get involved in any of this stuff until about a year ago.

Incidentally, that reminds me, I find mobo manuals difficult to understand - specifically the chapter on the BIOS. I turn to a page, and typically I see the following -

No-idea-what-this-means : Enabled

If you want to set "No-idea-what-this-means" to Enabled, then please choose Enabled. If you want to set "No-idea-what-this-means" to Disabled, then set it to Disabled. The problem is that I've got no idea what the option "No-idea-what-this-means" is, because it doesn't tell you.

I need to grab a book (or read a website) that tells you what all these weird BIOS settings mean. At the moment, a lot of my choices are 'educated' guesses.

retro games 100 wrote:

:lol: One reason I appear to be so stupid, is that I didn't get involved in any of this stuff until about a year ago. […]
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Davros wrote:

You took your time, I came to that conclusion ages ago 😁

🤣 One reason I appear to be so stupid, is that I didn't get involved in any of this stuff until about a year ago.

Incidentally, that reminds me, I find mobo manuals difficult to understand - specifically the chapter on the BIOS. I turn to a page, and typically I see the following -

No-idea-what-this-means : Enabled

If you want to set "No-idea-what-this-means" to Enabled, then please choose Enabled. If you want to set "No-idea-what-this-means" to Disabled, then set it to Disabled. The problem is that I've got no idea what the option "No-idea-what-this-means" is, because it doesn't tell you.

I need to grab a book (or read a website) that tells you what all these weird BIOS settings mean. At the moment, a lot of my choices are 'educated' guesses.

lolol

I agree about the manuals..
Let's not forget the are translated from chineese by someone from china 😁
But it's not the worst chineese-->english translations I've seen..

have a look at rojacks bios guide (allthough its amimed at modern pc's)
http://www.adriansrojakpot.com/Speed_Demonz/B … Guide_Index.htm