green 8bit isa slot means corrosion is all the way under SIMM sockets. Either traces of vias are eaten away there

The board appears to need a lot more work, before reliable POST can be expected.

To begin: I don't think alcohol rub alone, is enough to clear the corrosive substances. You need to neutralise pH with something like white vinegar first.

If you have not already done so, you should watch several hours of excellent motherboard repair example videos done by a fellow forum member. If you do as he does, I think your board will then have much better chances...

But it may even be, that the corrosion has gone too far. Some boards can be beyond repair.

Thank you for the quick reply Shreddoc. Over the last year and a half I have been watching board repair videos posted by Necroware on YouTube very often and I have been diving deep into computer architecture and trying to learn as much as I can. I really enjoyed watching Ben Eater's videos where he builds an entire microcomputer on breadboards using only 7400 series TTL ICs.

I will try cleaning the board with white vinegar as well. Should I dilute the white vinegar with water or mix it with anything else or is white vinegar alone fine? After applying it, how long should I let it stay? Should I rinse it off with water after? Sorry if my questions sound dumb. I have never used vinegar to clean boards before. I typically only use rubbing alcohol.

Also, do you know of any websites where I can find schematics for old 386 and 486 motherboards, low level diagnostics that I could perhaps burn onto an eeprom and/or other detailed information/tools that could help me diagnose and repair older motherboard. I am genuinely interested to learn more about how this hardware works at a very low level and how to repair it. I have a lot of old motherboards that I have saved from getting scrapped which I want to try to repair. My main goal is to learn more about the x86 platform and keep old hardware running.

Speaking of boards being beyond repair I fully understand. It is unfortunate when a board can't be saved. I have a board which has suffered so much damage from a leaking battery that the solder mask has starting peeling away from it. However, I feel like this board might be possible to save. At least I am optimistic.

BTW I have heard claims before that some 386 boards don't post without a working battery. Do I possibly need to install a new CMOS battery on this board. If so, how would I go about using the external battery header to achieve this. I remember reading information about this somewhere a few years back. I think it involved adding or removing a jumper to some pins near the old soldered on battery and possibly adding some resistors. I can't remember the exact details. Can someone help me figure out how to go about this? I think this is the next thing I will try.

rasz_pl wrote on 2022-05-20, 02:09:

green 8bit isa slot means corrosion is all the way under SIMM sockets. Either traces of vias are eaten away there

That honestly seems possible. I am not sure if I am comfortable trying to remove the ram slots right away since they have a lot of pins and I don't have any kind of desoldering equipment. All I have is a soldering iron and some flux and solder.
Any ideas how I can remove the slots without damaging them to check for corrosion below each memory slot? I hope I don't have to resort to this but I would like to know either way since I have other damaged boards on which I need to remove through hole components with multiple pins.

Nikola99 wrote on 2022-05-20, 06:33:

Any ideas how I can remove the slots without damaging them to check for corrosion below each memory slot?

The obvious way, by using desoldering equipment. A manual pump and a lot of patience + practice is the cheapest way and will do the job on old motherboards like this 386, albeit not very enjoyable.
You need at least a pump if you plan to fix motherboards, whenever there is battery damage you always need to remove neighboring components to check underneath.

Nikola99 wrote on 2022-05-20, 06:14:

Thank you for the quick reply Shreddoc. Over the last year and a half I have been watching board repair videos posted by Necrowa […]
Show full quote

Thank you for the quick reply Shreddoc. Over the last year and a half I have been watching board repair videos posted by Necroware on YouTube very often and I have been diving deep into computer architecture and trying to learn as much as I can. I really enjoyed watching Ben Eater's videos where he builds an entire microcomputer on breadboards using only 7400 series TTL ICs.

I will try cleaning the board with white vinegar as well. Should I dilute the white vinegar with water or mix it with anything else or is white vinegar alone fine? After applying it, how long should I let it stay? Should I rinse it off with water after? Sorry if my questions sound dumb. I have never used vinegar to clean boards before. I typically only use rubbing alcohol.

Also, do you know of any websites where I can find schematics for old 386 and 486 motherboards, low level diagnostics that I could perhaps burn onto an eeprom and/or other detailed information/tools that could help me diagnose and repair older motherboard. I am genuinely interested to learn more about how this hardware works at a very low level and how to repair it. I have a lot of old motherboards that I have saved from getting scrapped which I want to try to repair. My main goal is to learn more about the x86 platform and keep old hardware running.

Speaking of boards being beyond repair I fully understand. It is unfortunate when a board can't be saved. I have a board which has suffered so much damage from a leaking battery that the solder mask has starting peeling away from it. However, I feel like this board might be possible to save. At least I am optimistic.

BTW I have heard claims before that some 386 boards don't post without a working battery. Do I possibly need to install a new CMOS battery on this board. If so, how would I go about using the external battery header to achieve this. I remember reading information about this somewhere a few years back. I think it involved adding or removing a jumper to some pins near the old soldered on battery and possibly adding some resistors. I can't remember the exact details. Can someone help me figure out how to go about this? I think this is the next thing I will try.

I can't answer all of your many questions, but hopefully others will come along in time to contribute.

Regarding these questions:

Nikola99 wrote on 2022-05-20, 06:14:

I will try cleaning the board with white vinegar as well. Should I dilute the white vinegar with water or mix it with anything else or is white vinegar alone fine? After applying it, how long should I let it stay? Should I rinse it off with water after? Sorry if my questions sound dumb. I have never used vinegar to clean boards before. I typically only use rubbing alcohol.

I am not qualified to efficiently guide this. I really suggest to review some of the necroware videos, in particular, the ones in which he repairs 286/386/486 mainboards which have leaking batteries. There are several such videos in his collection, and most of them detail the process of proper removal, including the application of a pH neutraliser.

I think it would be difficult to repair such a board without having (for example) a ZD-915 station. Without, it could be very tedious and time consuming, and prone to making a mess.

Nikola99 wrote on 2022-05-20, 00:20:

Hello everyone, […]
Show full quote

Hello everyone,

I have an MST-386AWP motherboard fitted with an AMD 386 DX 40 which I can't get working.
I removed the leaking battery when I got the board a few months ago and cleaned up the battery acid using rubbing alcohol.
When I power the board on all I hear is one beep from the PC speaker regardless of whether the board is fitted with ram or not. My POST card always gives a code of 06 or 02.
My POST card's manual indicates that a code of 06 means "Uncompressing POST code next" and it does not say anything for a POST code of 02 for an AMI bios.
I looked around online and found information which suggests that one beep indicates a DRAM refresh error for AMI BIOS.
Thus, I have tried four different sets of 30 pin simms but I still get the same behavior regardless of what ram I use, how I install, or whether I install any ram.
I have checked the continuity of any traces that were near the leaking battery and they all appear to be fine.
I also checked the integrity of the traces which have been scratched near the ram slots on the bottom of the board and those are also fine. I was able to fix a socket 4 pentium board recently by repairing broken traces near the ram slots and was hoping this would also be the case here. Sadly, I don't think that is the issue with this board.
I then started to wonder if maybe the bios is corrupted so I pulled the bios chip out of the board and dumped it using my eeprom programmer. Based on what I can see the BIOS appears to be fine. I have attached the BIOS dump so you guys can have a look and give me a second opinion.
Please let me know if you have any ideas what else I could try? I am really hoping I can get this board working so I can build my first 386 system. I have a few other 386 boards as well but they are in much worse condition than this one.
Here are some pictures of the board and the POST card I am using:
https://imgur.com/a/9pcJy6o
This appears to be the closest match to my board in terms of component and jumper layout:
https://stason.org/TULARC/pc/motherboards/A/A … ache-DX-Ve.html

-Thank you

As others said, you need to perform a more thorough inspection of the damaged area, clean up the battery fuss with vinegar then IPA, fix possibly broken traces, etc.

Regarding the POST code situation, I want you to power on the board without any memory at all and report the beep sequence here. It should be a series of repeating hi/lo beeps, given the AMI bios you have.
The next thing would be to install the memory back, but no expansion cards (besides the tester), and report the beep codes and code sequence on the card. Should be 2 hi and a bunch of lows iirc.
And finally do the same reports as in the previous test, but with a video crd attached.

Doing all of this would be a good indicative of where to dig, if the trace issue is on the memory side, on the ISA bus, etc.
You can find the jumper manual on this page https://www.ultimateretro.net/en/motherboards/610

EDIT: as the board is not documented anywhere else, I made use of your photos and BIOS dump if you don't mind 😁

Shreddoc wrote on 2022-05-20, 07:50:

I can't answer all of your many questions, but hopefully others will come along in time to contribute. […]
Show full quote

Nikola99 wrote on 2022-05-20, 06:14:

Thank you for the quick reply Shreddoc. Over the last year and a half I have been watching board repair videos posted by Necrowa […]
Show full quote

Thank you for the quick reply Shreddoc. Over the last year and a half I have been watching board repair videos posted by Necroware on YouTube very often and I have been diving deep into computer architecture and trying to learn as much as I can. I really enjoyed watching Ben Eater's videos where he builds an entire microcomputer on breadboards using only 7400 series TTL ICs.

I will try cleaning the board with white vinegar as well. Should I dilute the white vinegar with water or mix it with anything else or is white vinegar alone fine? After applying it, how long should I let it stay? Should I rinse it off with water after? Sorry if my questions sound dumb. I have never used vinegar to clean boards before. I typically only use rubbing alcohol.

Also, do you know of any websites where I can find schematics for old 386 and 486 motherboards, low level diagnostics that I could perhaps burn onto an eeprom and/or other detailed information/tools that could help me diagnose and repair older motherboard. I am genuinely interested to learn more about how this hardware works at a very low level and how to repair it. I have a lot of old motherboards that I have saved from getting scrapped which I want to try to repair. My main goal is to learn more about the x86 platform and keep old hardware running.

Speaking of boards being beyond repair I fully understand. It is unfortunate when a board can't be saved. I have a board which has suffered so much damage from a leaking battery that the solder mask has starting peeling away from it. However, I feel like this board might be possible to save. At least I am optimistic.

BTW I have heard claims before that some 386 boards don't post without a working battery. Do I possibly need to install a new CMOS battery on this board. If so, how would I go about using the external battery header to achieve this. I remember reading information about this somewhere a few years back. I think it involved adding or removing a jumper to some pins near the old soldered on battery and possibly adding some resistors. I can't remember the exact details. Can someone help me figure out how to go about this? I think this is the next thing I will try.

I can't answer all of your many questions, but hopefully others will come along in time to contribute.

Regarding these questions:

Nikola99 wrote on 2022-05-20, 06:14:

I will try cleaning the board with white vinegar as well. Should I dilute the white vinegar with water or mix it with anything else or is white vinegar alone fine? After applying it, how long should I let it stay? Should I rinse it off with water after? Sorry if my questions sound dumb. I have never used vinegar to clean boards before. I typically only use rubbing alcohol.

I am not qualified to efficiently guide this. I really suggest to review some of the necroware videos, in particular, the ones in which he repairs 286/386/486 mainboards which have leaking batteries. There are several such videos in his collection, and most of them detail the process of proper removal, including the application of a pH neutraliser.

I think it would be difficult to repair such a board without having (for example) a ZD-915 station. Without, it could be very tedious and time consuming, and prone to making a mess.

Thanks again for the quick reply. I did a more thorough visual inspection of the board and I don't think any battery acid got to the memory slots. The only places I see battery acid is near the keyboard connector and a bit in the top most ISA slot. I will clean those areas with white vinegar. Also, I think it is probably time for me to get my hands on a desoldering station. Given that I have a lot of boards I want to fix and at least some will need to have components removed I think it is a worthwhile investment.

computerguy08 wrote on 2022-05-20, 09:05:

As others said, you need to perform a more thorough inspection of the damaged area, clean up the battery fuss with vinegar then […]
Show full quote

Nikola99 wrote on 2022-05-20, 00:20:

Hello everyone, […]
Show full quote

Hello everyone,

I have an MST-386AWP motherboard fitted with an AMD 386 DX 40 which I can't get working.
I removed the leaking battery when I got the board a few months ago and cleaned up the battery acid using rubbing alcohol.
When I power the board on all I hear is one beep from the PC speaker regardless of whether the board is fitted with ram or not. My POST card always gives a code of 06 or 02.
My POST card's manual indicates that a code of 06 means "Uncompressing POST code next" and it does not say anything for a POST code of 02 for an AMI bios.
I looked around online and found information which suggests that one beep indicates a DRAM refresh error for AMI BIOS.
Thus, I have tried four different sets of 30 pin simms but I still get the same behavior regardless of what ram I use, how I install, or whether I install any ram.
I have checked the continuity of any traces that were near the leaking battery and they all appear to be fine.
I also checked the integrity of the traces which have been scratched near the ram slots on the bottom of the board and those are also fine. I was able to fix a socket 4 pentium board recently by repairing broken traces near the ram slots and was hoping this would also be the case here. Sadly, I don't think that is the issue with this board.
I then started to wonder if maybe the bios is corrupted so I pulled the bios chip out of the board and dumped it using my eeprom programmer. Based on what I can see the BIOS appears to be fine. I have attached the BIOS dump so you guys can have a look and give me a second opinion.
Please let me know if you have any ideas what else I could try? I am really hoping I can get this board working so I can build my first 386 system. I have a few other 386 boards as well but they are in much worse condition than this one.
Here are some pictures of the board and the POST card I am using:
https://imgur.com/a/9pcJy6o
This appears to be the closest match to my board in terms of component and jumper layout:
https://stason.org/TULARC/pc/motherboards/A/A … ache-DX-Ve.html

-Thank you

As others said, you need to perform a more thorough inspection of the damaged area, clean up the battery fuss with vinegar then IPA, fix possibly broken traces, etc.

Regarding the POST code situation, I want you to power on the board without any memory at all and report the beep sequence here. It should be a series of repeating hi/lo beeps, given the AMI bios you have.
The next thing would be to install the memory back, but no expansion cards (besides the tester), and report the beep codes and code sequence on the card. Should be 2 hi and a bunch of lows iirc.
And finally do the same reports as in the previous test, but with a video crd attached.

Doing all of this would be a good indicative of where to dig, if the trace issue is on the memory side, on the ISA bus, etc.
You can find the jumper manual on this page https://www.ultimateretro.net/en/motherboards/610

EDIT: as the board is not documented anywhere else, I made use of your photos and BIOS dump if you don't mind 😁

Thank you for the reply. I did a closer visual inspection yesterday. No traces seem to be damaged and there is no battery acid on the memory slots.
I did try powering on the board with no ram, with half the slots populated, no slots populated, with and without a video card. I always get a 02 or 06 error code on thw POST card and one beep from the speaker.
The only thing I haven't tried yet is pulling out the cache. Also, is it possible that the board is refusing to boot since there is no working battery connected to it? I have heard that some 386 boards will refuse to POST without a working cmos battery. I want to try attaching one using the external header. Do you know how I need to connect the external battery to the 4 pin external battery header. I have never used the external battery header on any of my other motherboards before?

I glad to hear that the bios dumps and photos were helpful. Do you have the same board? If so, could you verify if my bios is good. I want to make sure there isn't an issue with my board's bios before I dig deeper into the board's hardware.
Now that I have an eeprom programmer I would be happy to share more bios dumps if anyone is interested. I have a few boards on which not much documentation is available.

Can you post some pictures of your board?

chrismeyer6 wrote on 2022-05-20, 20:49:

Can you post some pictures of your board?

You can see pictures of my board by following this link:
https://imgur.com/a/9pcJy6o

It's hard to tell from the pictures but it looks like there might be corrosion on components to the right as well as under the ram slots.

An image of your board, for reference:

Notice the yellow arrow showing how visible corrosion has, in some areas, clearly reached quite a wide radius away from the battery.

--

Now I will reference the following video, for comparison. This shows how it should be done:
Will this 286 mainboard ever work again? Heavy damage by leaky battery
from Youtube channel 'Necroware' :
https://www.youtube.com/watch?v=XdT0byPMnZY

Here is an image showing how his similar board looked before, and after his long cleaning phase:

Notice how your board is still full of green-coloured corrosive substance and oxidation, despite your claims of having finished cleaning it. Compare Necroware's "After" image - the green is almost entirely cleaned away, and ALL suspect traces and components are re-done or replaced.

Your board is not clean! Nowhere near!

You have a lot of work still to do, for any chance of the board being considered Repaired.

Look at the following three images, showing just some of the many steps taken by Necroware, in the proper cleaning of his board:

Shreddoc wrote on 2022-05-20, 22:37:

An image of your board, for reference: […]
Show full quote

An image of your board, for reference:

your_board_now.jpg

Notice the yellow arrow showing how visible corrosion has, in some areas, clearly reached quite a wide radius away from the battery.

--

Now I will reference the following video, for comparison. This shows how it should be done:
Will this 286 mainboard ever work again? Heavy damage by leaky battery
from Youtube channel 'Necroware' :
https://www.youtube.com/watch?v=XdT0byPMnZY

Here is an image showing how his similar board looked before, and after his long cleaning phase:

necroware_example_work.jpg

Notice how your board is still full of green-coloured corrosive substance and oxidation, despite your claims of having finished cleaning it. Compare Necroware's "After" image - the green is almost entirely cleaned away, and ALL suspect traces and components are re-done or replaced.

Your board is not clean! Nowhere near!

You have a lot of work still to do, for any chance of the board being considered Repaired.

Look at the following three images, showing just some of the many steps taken by Necroware, in the proper cleaning of his board:

necroware_clean1.jpg

necroware_clean2.jpg

necroware_clean3.jpg

Thank you for the detailed photos. I will indeed clean the board further using white vinegar as I mentioned in my earlier post. I will post an update here once I have done so and am hopefully closer to getting the board working.

Nikola99 wrote on 2022-05-21, 05:47:

am hopefully closer to getting the board working.

you arent 🙁

>Over the last year and a half I have been watching board repair videos posted by Necroware

yet you didnt even clean the corrosion properly 🙁. This board requires desoldering a shitton of components and fixing broken traces/vias. This is what it would take https://www.eevblog.com/forum/repair/corrosio … y-nicd-battery/ You would require $100-200 in equipment and a lot of experience (watching hours of repairs wasnt enough to pick up basics) to maybe end up with working $50 motherboard. I suggest you buy another board, and maybe sent this one to Necroware.

Nikola99 wrote on 2022-05-20, 19:15:

Thank you for the reply. I did a closer visual inspection yesterday. No traces seem to be damaged and there is no battery acid o […]
Show full quote

Thank you for the reply. I did a closer visual inspection yesterday. No traces seem to be damaged and there is no battery acid on the memory slots.
I did try powering on the board with no ram, with half the slots populated, no slots populated, with and without a video card. I always get a 02 or 06 error code on thw POST card and one beep from the speaker.
The only thing I haven't tried yet is pulling out the cache. Also, is it possible that the board is refusing to boot since there is no working battery connected to it? I have heard that some 386 boards will refuse to POST without a working cmos battery. I want to try attaching one using the external header. Do you know how I need to connect the external battery to the 4 pin external battery header. I have never used the external battery header on any of my other motherboards before?

I glad to hear that the bios dumps and photos were helpful. Do you have the same board? If so, could you verify if my bios is good. I want to make sure there isn't an issue with my board's bios before I dig deeper into the board's hardware.
Now that I have an eeprom programmer I would be happy to share more bios dumps if anyone is interested. I have a few boards on which not much documentation is available.

Lack of barrel battery will not impact the boot procedure. However, looking at the photos again, I notice some extensive damage which is quite hard to fix by a novice unfortunately. You'd have to take out all the components in the top left corner and slowly poke at all the traces for continuity, which is quite time consuming. I also don't have this board, so I can't assist you with that either.

That being said, I would be interested in more BIOS dumps, if you say you have some undocumented boards, they're always welcome.

Shreddoc wrote on 2022-05-20, 07:50:

I think it would be difficult to repair such a board without having (for example) a ZD-915 station. Without, it could be very tedious and time consuming, and prone to making a mess.

Testimonial here! I can confirm that a good soldering station is both a good investment and a good instrument to avoid any bad result.
Plus, you will desolder through 20 layers of jeans and aluminium cans!!

Watch tutorials and learn stuff by heart. Necroware is a very good start indeed.