steevf wrote on 2024-02-17, 19:22:

I've been trying to get a 486 build but I have run in to some issues that I just can't figure out. There is the system specs: […]
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I've been trying to get a 486 build but I have run in to some issues that I just can't figure out.
There is the system specs:

AOpen Vi15G-4
CPU: Intel 486 DX2-66
RAM 72 MB (2x 4MB + 1x 64MB)
Cache: 256KB
video: Chips F64300 (1MB) (Rather fast card)
The BIOS Version: R2.2 (date 12/15/93)
The BIOS will detect my CF cards (2GB and 4GB) just fine. (Although it is a manually initiated detection.)
Gotek Floppy

So, what keeps happening is I get write failures on drive C. This happens often but very randomly when trying to copy or modify files).

I don't seem to ever get this error when I format or fdisk the drive.

I've double checked all the jumpers on the motherboard.
I've tried three different IDE/VLB controller cards from three different eras:
1. DTC 2278E (dual IDE no BIOS) (1995)
2. VL 400GG GoldStar Prime 2 IDE Controller Card (Single IDE no bios) (1993)
3. Older Winbond 83757F (single IDE VLB or ISA) (1992)
I've tried different IDE cables
I've tried different CF cards
I've tried different CF card adapters.
I've put deoxit on all the connectors, and jumpers.
I've tried jumper settings for > 33MHz and <=33 MHz, 0-1 wait states on the motherboard. (the bus speed should be 33MHz because the CPU I'm using).
I've even tried disabling VLB on the controller that allowed it(Winbond) and just use ISA for the IDE.

The system seems rather stable in everything else except for writing to the HD.

I'm not sure what else I can try.
I've thought about the BIOS update to 2.3 but I will need to source a PROM to do that which is getting super difficult.

Aside from the BIOS update could there be anything else I'm missing?
Anyone have any ideas?

It is always the RAM.
Is one of the 3 SIMMs EDO (which is not supported, you need to use FPM in case you don't know it)?
Are you sure the 64MB module is supported by the board?
Do you have the same problem with only the 2 times 4MB?
Which operating system do you use? DOS?

EDIT: And I hope you don't run the CPU without a heatsink. Don't laugh, some people are really doing it, because they got the board + CPU, but no heatsink 😁

More information about the memory:
It is a strange config but the motherboard documentation lists it as a supported configuration.

Here is what I found on the memory:
The two 4MB sticks in bank 0 and 1 are: Samsung KMM5361000AG-8 (80-ns FPM)
The 64MB stick is in bank 2 is: Smart Technologies sm536164084c4s6 (60-ns EDO)

All three sticks test good.

Since the 64MB module is not FPM, I pulled it out.

Tried the DOS 6.21 installation from floppy again on freshly formatted drive c just using the two 4MB FPM modules.
The install fails half way through with write errors to drive C. No change.

Well, it's a 486, so one stick of ram will do. just try each one of them separately if supported.

What brand(s) of CompactFlash cards are you using?

Have you tried with a regular HDD?

Well, I tried each stick individually, still does the same thing. (edit: meaning each 4MB stick individually, the system doesn't post with the 64MB EDO)

A few other things I tried was disabling Video caching in BIOS and tried turning on and off IDE Block mode. No changes.
And yes, LBA mode is on or it won't properly detect the CF cards sizes.

If I ever get this thing working it I will eventually put a sound card in, a network card and Windows for Workgroups 3.11.

Shponglefan wrote on 2024-02-17, 20:30:

What brand(s) of CompactFlash cards are you using?

Have you tried with a regular HDD?

I don't have any working HDDs
The CF cards I've tried are:
* Transcend 133 2GB
* Verbatim 4BG
The same cards I use for my 286, 386DX and Pentium-200 builds.

steevf wrote on 2024-02-17, 20:41:

Well, I tried each stick individually, still does the same thing. […]
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Well, I tried each stick individually, still does the same thing.

A few other things I tried was disabling Video caching in BIOS and tried turning on and off IDE Block mode. No changes.
And yes, LBA mode is on or it won't properly detect the CF cards sizes.

If I ever get this thing working it I will eventually put a sound card in, a network card and Windows for Workgroups 3.11.

My 486 does strange things when LBA mode is on. Sometimes data cannot be read. Can you have the motherboard auto detect the CF card in the BIOS and then disable LBA mode after the detection?

Have you tried without the cache memory ? ie disabling external L2 cache in bios and testing.

weedeewee wrote on 2024-02-17, 20:57:

Have you tried without the cache memory ? ie disabling external L2 cache in bios and testing.

Hmm that is an interesting thing to try.
I'm not sure how cache works on this MB.
There are two settings for Write/Back and Write/Thru, and I'm not sure which one it should be.
The other settings are to enable/disable external cache and enable/disable internal cache.

for now, I'd say, disable both internal & external and test again.

steevf wrote on 2024-02-17, 20:46:

I don't have any working HDDs The CF cards I've tried are: * Transcend 133 2GB * Verbatim 4BG The same cards I use for my […]
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I don't have any working HDDs
The CF cards I've tried are:
* Transcend 133 2GB
* Verbatim 4BG
The same cards I use for my 286, 386DX and Pentium-200 builds.

How are you running these cards on the 286 or 386 builds? Are you using a BIOS extension or overlay software at all?

Are you using anything like that with the 486 build?

Do you have any other cards to test that are smaller (e.g. 512MB or less)?

weedeewee wrote on 2024-02-17, 21:11:

for now, I'd say, disable both internal & external and test again.

Didn't fix it. It still comes up errors on C. But it did it in slow mo this time. 😀

Have another computer? Or different motherboard. BTW, please no EDO memory.

Cheers,

Shponglefan wrote on 2024-02-17, 21:30:

How are you running these cards on the 286 or 386 builds? Are you using a BIOS extension or overlay software at all?

Are you using anything like that with the 486 build?

Do you have any other cards to test that are smaller (e.g. 512MB or less)?

The 286 and 386 have XTIDEUB.
I'm just using the motherboard BIOS as it has LBA mode and can detect the CF cards up to 8BG. No overlay software. Most of my testing as been boot from floppy and try to install the OS. It usually errors out in the process somewhere. I have gotten to the point where I can boot to the CF card and copy files from a floppy and it will error out the same way. Even tried copying files on the same drive from C: to D: partitions it will still eventually give me a write error. It always seems to be a write error.

The smallest card I have is 1BG and it's tucked away inside my 286 luggable and not worth digging out honestly.

zuldan wrote on 2024-02-17, 20:47:

My 486 does strange things when LBA mode is on. Sometimes data cannot be read. Can you have the motherboard auto detect the CF card in the BIOS and then disable LBA mode after the detection?

Yeah i did try that but it didn't make a difference.

steevf wrote on 2024-02-17, 21:48:

zuldan wrote on 2024-02-17, 20:47:

My 486 does strange things when LBA mode is on. Sometimes data cannot be read. Can you have the motherboard auto detect the CF card in the BIOS and then disable LBA mode after the detection?

Yeah i did try that but it didn't make a difference.

What motherboard BIOS version are you using?

pentiumspeed wrote on 2024-02-17, 21:35:

Have another computer? Or different motherboard. BTW, please no EDO memory.

Cheers,

All my other systems are stable and I don't want to mess with them.
This is the only 486 motherboard I have. I guess I could try finding a PCI 486 motherboard and abandon the VLB stuff altogether.

Yeah that EDO stick is out. It would work better in my Pentium-200 system anyway if I didn't already have that computer maxed out at 128 MB.

steevf wrote on 2024-02-17, 21:46:

The 286 and 386 have XTIDEUB.
I'm just using the motherboard BIOS as it has LBA mode and can detect the CF cards up to 8BG. No overlay software.

Try using XTIDE with the 486 and see if that makes any difference.

If you can recreate the conditions under which the cards work with the 286/386, it might narrow it down to a specific issue with the BIOS in your 486.

got any IDE block mode setting in the bios ?