Alright, just to give closure to this thread after a long time 😀 I'm going through some organizing of my storage because I'm moving, found these boards again and thought on writing a "conclusion".

The 486 board is now part of a pile I'll take to a recycler. I didn't trust my ability to fix it with that damage, and over time I started taking pieces out of it to fix other boards (or rather, to test possible fixes to then do them properly with new components)

The 386 motherboard I got it to work, not sure if I actually installed all caps with the proper values but it is booting. As the power connector was one of the things corroded, I installed the power connector from the 486 board 😀

Regards

carlitosbala wrote on 2022-03-18, 00:21:

Alright, just to give closure to this thread after a long time :) I'm going through some organizing of my storage because I'm mo […]
Show full quote

Alright, just to give closure to this thread after a long time 😀 I'm going through some organizing of my storage because I'm moving, found these boards again and thought on writing a "conclusion".

The 486 board is now part of a pile I'll take to a recycler. I didn't trust my ability to fix it with that damage, and over time I started taking pieces out of it to fix other boards (or rather, to test possible fixes to then do them properly with new components)

The 386 motherboard I got it to work, not sure if I actually installed all caps with the proper values but it is booting. As the power connector was one of the things corroded, I installed the power connector from the 486 board 😀

Regards

Dumping even a defect 486 board is a sin and you'll end up in hell for this 😀
Maybe this helps: https://www.ultimateretro.net/en/motherboards/1933

However, at least you try to find somebody who would take it for the shipping costs. The worst thing that can happen is that it will be used for spare parts to repair another board.
Please don't dump it 😀

HanSolo wrote on 2022-03-18, 01:00:

Dumping even a defect 486 board is a sin and you'll end up in hell for this :) Maybe this helps: https://www.ultimateretro.net/e […]
Show full quote

carlitosbala wrote on 2022-03-18, 00:21:

Alright, just to give closure to this thread after a long time :) I'm going through some organizing of my storage because I'm mo […]
Show full quote

Alright, just to give closure to this thread after a long time 😀 I'm going through some organizing of my storage because I'm moving, found these boards again and thought on writing a "conclusion".

The 486 board is now part of a pile I'll take to a recycler. I didn't trust my ability to fix it with that damage, and over time I started taking pieces out of it to fix other boards (or rather, to test possible fixes to then do them properly with new components)

The 386 motherboard I got it to work, not sure if I actually installed all caps with the proper values but it is booting. As the power connector was one of the things corroded, I installed the power connector from the 486 board 😀

Regards

Dumping even a defect 486 board is a sin and you'll end up in hell for this 😀
Maybe this helps: https://www.ultimateretro.net/en/motherboards/1933

However, at least you try to find somebody who would take it for the shipping costs. The worst thing that can happen is that it will be used for spare parts to repair another board.
Please don't dump it 😀

I second that, please don't dump it - especially as prices for 486 probably doubled since your original post.

And, shame on the Vogons community for not giving any advice - I myself obviously know a bit less than Jon Snow, but some others here, you could do better!

Alright, I guess I can do a final pass on it, it's true that it is a shame to destroy it. I did notice the prices have been going up, I'm regretting trading my Am486 DX4 120 CPU for a few ISA cards last year. But at the same time, aside from a small group of enthusiasts, there isn't a lot of interest in my country for this kind of thing, it's more collectors getting CPUs than retro-gamers wanting full machines. I got the two boards I was asking about here, plus a 286 board with a Harris 25MHz CPU for the equivalent of 30 USD from a recycler. And as for shipping, I doubt anyone will be interested in paying 40USD in shipping only unless the hardware is extremely rare

As it happens, I have another broken 486 board that had the BIOS chip put backwards when I got it (unfortunately only realized it after it got quite hot) that I'm keeping in case I eventually get a BIOS programmer, the one I bought via ebay in October 2020 should be arriving any time soon...

Sorry, I digress.

HanSolo, thanks for the link, although the photo is the same I'm linking in my post. I still don't know what the values of the two caps in the top-left (near the chokes) should be, nor I have the traces to know whether those chokes should go in parallel or belong to different traces. Any hint regarding how I should attempt the repair would be very appreciated.

Cuttoon, I just assume the board might be an uncommon one and not many people have it. Between these being old enough to be forgotten by most of the web, plus the fact that sometimes the hardware I get is a localized model with different model ID than the version sold in Europe or the US, sometimes I simply assume the info is not there anymore.

I'll try to put the board together again, first the pieces I took out of it (mainly chips and a few caps, plus the power connector) and then what was missing from the beginning. I'll report the progress here if you are interested 😁

The truth is I'm probably leaving this hardware hobby behind, for some time at least. I won't be able to take my "iron wives" (as my wife calls the PCs I have in the garage) to my new place, so I'm trying to find new homes for what works, and get rid of what doesn't. It would be awesome if this one can be in the "working" pile at the end

Regards

Edit: nevermind the values of the caps in the corner, I reviewed the board and they are in place, no need to replace them

I'm afraid I won't be a big help since my hardware-fixing-skills are less than mediocre. I know how to hold a soldering iron but not how to find the actual problems. And repairing mainboards might be extra-hard because at some point in time they used multilayer-boards.

But at least I found the original source of the photo of the mainboard: https://www.clous.cz/motherboard-kolekce-2/ (scroll down to DTK PKM-0037S). Seems to be a collector from the Czech Republic, so maybe he could be asked for more detailed information.

I must admit that storing broken hardware is somewhat silly. It's only that 486-boards are getting rarer so I thought that even a broken one could at least serve as a donator for spare parts.

I took a shot and wrote an email, with some luck I can get some additional info 😀

My knowledge of hardware is quite limited too, I can only count a couple of successes with plenty of failures, but I'm still trying to learn and every board that gets back to life is a huge achievement 🙂

Thanks for your help so far