Horun wrote on 2023-02-27, 00:40:

danieljm, Are you running a MMX cpu ? You have it set to 2.8v core.
Right ! they have solder pads for a possble coin cell holder, see here: https://theretroweb.com/motherboard/image/m54 … 53941170738.jpg
Where the little map of N/S America, two pads and one looks like it has a + symbol (right one)....and what could be a 4pin external header location just below

Hey Horun,

This isn't my thread, I was just trying to offer a comparison to my board which I know to be an M549. I think you meant to ask that question to thisab. 😀

Cheers.

danieljm wrote on 2023-02-27, 00:54:

Hey Horun, […]
Show full quote

Horun wrote on 2023-02-27, 00:40:

danieljm, Are you running a MMX cpu ? You have it set to 2.8v core.
Right ! they have solder pads for a possble coin cell holder, see here: https://theretroweb.com/motherboard/image/m54 … 53941170738.jpg
Where the little map of N/S America, two pads and one looks like it has a + symbol (right one)....and what could be a 4pin external header location just below

Hey Horun,

This isn't my thread, I was just trying to offer a comparison to my board which I know to be an M549. I think you meant to ask that question to thisab. 😀

Cheers.

Yes. Sorry I copied your name instead of thisab when I posted. My bad. Old farts make mistakes, and the older I get the more I make 😁

Battery. If it's of any help.
Houston Tech HT12888A Real Time - battery hack

CoffeeOne wrote on 2023-02-26, 10:55:

Hello,

And one more question: Are you sure that those 2 8MB modules are compatible to each other? They look very different. But hard to tell from this picture.

I also have this consern.

But I see you are now using another memory stick that also may not be supported. Try a 16 chip 32 mb stick. Or a matching set of 8 or 16mb simms

Anyway, reset bios to defaults, disable ide and floppy, disable shadow ram, disable pci functions. Etc. see if you can get some change.

Also try a different video card, and check IRQ plug n play settings

(Try without diag card just to try everything also)

But anyway, code 52 appears to be a issue initializing your isa option roms
So play with the shadowing options and memory options in bios.

The only card you have with an option rom is the video card, I would suspect it not to be the problem as it has already loaded, but it may be trying to shadow it? Idk.

Horun: Yes, its an MMX CPU and Ive set it to 2.8v and P55C like the manual instructed for this kind of CPU.

As an update:
- Ive swapped the CPU with another CPU (a 233MHZ MMX). Same thing.
- Swapped the RAM to two FPM 4MB. Still the same problem.

At this point, I think its either the BIOS or something else wrong with the board.
Anyhow, Motherboard seems to be the culprit.

thisab wrote on 2023-02-26, 21:46:

Doornkaat: Yea, I was surprised at first, but I saw a lot of (bad) comments about these PCChips on Vogons. However I dont have that kind of equipment 🙁 .

Do you have another motherboard with a 32pin BIOS EEPROM that you can use to hotflash the possibly faulty EEPROM?
Even a PCI NIC with 32pin socket may be enough.

Try a new bios chip. Could be a writing cycle limit reached.
NVRAM update not happening, as already posted a few times.

The NVRAM theory makes a lot of sense.
I got another board (m571v32) and "transplanted" all the components from m549 and its all working fine. That m571 board has a problem with DIMM2 socket tho (any stick of RAM there reduces the clock speed of the processor to 175MHz and when I run a memtest it reboots). Runs fine with EDO or with DIMM1 populated.

Maybe replacing the m549 BIOS chip and copying to another one might solve the problem.

Never used an EEPROM programmed before.. Ive bought a Sp200se from China. Is that enough?

thisab wrote on 2023-03-15, 18:54:

The NVRAM theory makes a lot of sense. I got another board (m571v32) and "transplanted" all the components from m549 and its al […]
Show full quote

The NVRAM theory makes a lot of sense.
I got another board (m571v32) and "transplanted" all the components from m549 and its all working fine. That m571 board has a problem with DIMM2 socket tho (any stick of RAM there reduces the clock speed of the processor to 175MHz and when I run a memtest it reboots). Runs fine with EDO or with DIMM1 populated.

Maybe replacing the m549 BIOS chip and copying to another one might solve the problem.

Never used an EEPROM programmed before.. Ive bought a Sp200se from China. Is that enough?

It should have a bios chips compatibility .pdf somewhere.
I use a TL866+.
Wait for some knowledgeable people.

Nexxen wrote on 2023-03-16, 01:21:

It should have a bios chips compatibility .pdf somewhere. I use a TL866+. Wait for some knowledgeable people. […]
Show full quote

thisab wrote on 2023-03-15, 18:54:

The NVRAM theory makes a lot of sense. I got another board (m571v32) and "transplanted" all the components from m549 and its al […]
Show full quote

The NVRAM theory makes a lot of sense.
I got another board (m571v32) and "transplanted" all the components from m549 and its all working fine. That m571 board has a problem with DIMM2 socket tho (any stick of RAM there reduces the clock speed of the processor to 175MHz and when I run a memtest it reboots). Runs fine with EDO or with DIMM1 populated.

Maybe replacing the m549 BIOS chip and copying to another one might solve the problem.

Never used an EEPROM programmed before.. Ive bought a Sp200se from China. Is that enough?

It should have a bios chips compatibility .pdf somewhere.
I use a TL866+.
Wait for some knowledgeable people.

Well, some update, ripped the label from the BIOS chip, but I could not find any info as to what the heck is this chip:
An MT12097 H.T.
Totally blank at the bottom.

I could not find any info on that thing...

thisab wrote on 2023-04-02, 13:18:

Well, some update, ripped the label from the BIOS chip, but I could not find any info as to what the heck is this chip: An MT120 […]
Show full quote

Nexxen wrote on 2023-03-16, 01:21:

It should have a bios chips compatibility .pdf somewhere. I use a TL866+. Wait for some knowledgeable people. […]
Show full quote

thisab wrote on 2023-03-15, 18:54:

The NVRAM theory makes a lot of sense. I got another board (m571v32) and "transplanted" all the components from m549 and its al […]
Show full quote

The NVRAM theory makes a lot of sense.
I got another board (m571v32) and "transplanted" all the components from m549 and its all working fine. That m571 board has a problem with DIMM2 socket tho (any stick of RAM there reduces the clock speed of the processor to 175MHz and when I run a memtest it reboots). Runs fine with EDO or with DIMM1 populated.

Maybe replacing the m549 BIOS chip and copying to another one might solve the problem.

Never used an EEPROM programmed before.. Ive bought a Sp200se from China. Is that enough?

It should have a bios chips compatibility .pdf somewhere.
I use a TL866+.
Wait for some knowledgeable people.

Well, some update, ripped the label from the BIOS chip, but I could not find any info as to what the heck is this chip:
An MT12097 H.T.
Totally blank at the bottom.

I could not find any info on that thing...

Try a 12V 28F001BX-T, that's the one I used as I also had a rebranded EEPROM chip H.T. xxxx.
Anything compatible with this https://html.alldatasheet.com/html-pdf/66024/ … 28F001BX-T.html will probably work.
1-MBIT (128K x8) 12V

I have an identical card, it had some faults, two I fixed, one was the Dallas-like chip, I made a change, but it only serves to store in the BIOS, it had a completely flat battery, the first problem was with the RAM, fixed by doing a bridge over a track in the back, the last problem (which I haven't solved) is the L2 cache, it doesn't work, and when starting the PC it crashes.
I got around this problem (for the moment), by disabling the L2 cache from the BIOS, and by memorizing this setting, the PC starts up, even if it is slower.
I ran a K6-2-400 at 360MHz (60 6X), putting the VCore jumpers at 2.5V, I could if I had a K6-3 ignore the bad cache problem, since it's integrated in that CPU (256KB).
I don't remember which page of the link, but if you have time and patience, you can find interesting ideas (I hope they can help you), I didn't understand if you can enter the BIOS, but try holding DEL or DEL immediately after turning on the PC.

Re: Test and troubleshoot PC@LIVE motherboards

I just wanted to update this thread. I now have a programmer and flashed many BIOSes from https://theretroweb.com/motherboards/s/pcchips-m520#bios and used MX28F1000P as the base CHIP (09/26/97-i430VX-02271997C-00, 09/15/97-i430VX-02271997C-00, 03/03/97-i430VX-02071997C-00). All of them worked, but still got code 52.

Tried other EDO and SDRAM and got the exact same problem. Also tried disabling everything (cache, Shadow, etc). Nothing... Swaped the processor, same thing. Swapped the PSU, same thing.

Im at a loss..

Code 52 happens when checking IDE drives.
Must be connected somehow.

Could you post high res pics of the board? Maybe some trace got cut.