386DX https://alexandrugroza.ro/microelectronics/sy … sbmc/index.html
486sx SiS 85C460 98134-925-009_DeskMaster_486Q_SD925E_Service_Manual_1993 https://archive.org/details/bitsavers_samsung … al1993_10429634

Intel had some schematics that may be useful: http://web.archive.org/web/20000815093339/htt … intarch/schems/
like this: http://web.archive.org/web/20000816201259/htt … hems/ulpsch.htm
be sure to DL from their webserver, not the ftp servers...

Am486 Microprocessor PCI Customer Development Platform User's Manual Order #22408A

Am486 Microprocessor PCI Customer Development Platform Schematics

Roman555 wrote on 2023-02-18, 11:08:

Am486 Microprocessor PCI Customer Development Platform User's Manual Order #22408A

Am486 Microprocessor PCI Customer Development Platform Schematics

Thanks ! I remebered you also found that Mitac 5023 schematic: Re: UMC8881/8886 Datasheet

Roman555 wrote on 2023-02-18, 11:08:

Am486 Microprocessor PCI Customer Development Platform User's Manual Order #22408A

Am486 Microprocessor PCI Customer Development Platform Schematics

altho it is for official AMD devboard https://www.datasheetarchive.com/pdf/download … m=ALi%2520M5113
its similar enough to something like this https://theretroweb.com/motherboards/s/unknow … ci1487-89-m5113

Horun wrote on 2023-02-18, 15:24:

Thanks ! I remebered you also found that Mitac 5023 schematic: Re: UMC8881/8886 Datasheet

Welcome! I think it's interesting to look into schematics of computer systems 😀

rasz_pl wrote on 2023-02-18, 18:50:

altho it is for official AMD devboard https://www.datasheetarchive.com/pdf/download … m=ALi%2520M5113
its similar enough to something like this https://theretroweb.com/motherboards/s/unknow … ci1487-89-m5113

Maybe it's by Acer

P.S. Schematics of Samsung and early Intel were downloaded. Thanks for links!

I have about 170MB of Intel Schems, Reference and Dev board, related manuals.
attached a dir.txt if anyone is interested in anything will add it here os up it all to archive org...
anything with sch, schem, etc in title has schematics in the pdf....

Thanks everyone for the links 😁 (if You can then add more )
I take everything 286/386/486 and early Pentium schematics . It would be good if moderator creates a topic with "schematics" .
I also have a PDF with the description of the chipsets . I can add to the forum.
Too bad the producers don't publish old schematics .The technique is too old, so no one will copy it today 😀 .

Example of a board for which the chipset description cannot be found . I used someone's link from this forum but I have the same motherboard Re: Try to fix old 786 ACIO VESA 386/486 Motherboard
USAi SC-9204-A chipset .
Next example , ALI chipset description cannot be found ALI 1429 A1 and ALI M1431 A2 .

Here is an interesting link to the chipset datascheet http://ftpmirror.your.org/pub/misc/bitsavers/components/

Horun , do You have these documentation on an ftp site or something similar ? I take everything .

Also, I'd like to remind about a wonderful site https://elektrotanya.com where schematics of not so vintage electronic devices can be found.
And if it's allowed I'll attach torrent file for notebook schematics (not modern nor vintage ones from site kythuatphancung).

tomaszdko wrote on 2023-02-20, 05:55:

Next example , ALI chipset description cannot be found ALI 1429 A1 and ALI M1431 A2 .

In most of cases schematics and datasheets for exact motherboard or chipset are not necessary. Usually similar ones and some knowledge and experience are enough for repair.
Obviously I don't mean engineering a new device or adding extra functional in a present one.

Roman555 wrote on 2023-02-20, 16:21:

Also, I'd like to remind about a wonderful site https://elektrotanya.com where schematics of not so vintage electronic devices c […]
Show full quote

Also, I'd like to remind about a wonderful site https://elektrotanya.com where schematics of not so vintage electronic devices can be found.
And if it's allowed I'll attach torrent file for notebook schematics (not modern nor vintage ones from site kythuatphancung).

tomaszdko wrote on 2023-02-20, 05:55:

Next example , ALI chipset description cannot be found ALI 1429 A1 and ALI M1431 A2 .

In most of cases schematics and datasheets for exact motherboard or chipset are not necessary. Usually similar ones and some knowledge and experience are enough for repair.
Obviously I don't mean engineering a new device or adding extra functional in a present one.

Roman555 don't be smart than you think you are . First thing what we do it is not read the documentation .Sometimes you have a motherboard checked , looking good but still "dark monitor screen" .
Sometimes documentation can be useful to "find" an atypical error. It's good having hard to find documentation ,just in case .

tomaszdko wrote on 2023-02-21, 14:23:

Roman555 don't be smart than you think you are . First thing what we do it is not read the documentation .Sometimes you have a motherboard checked , looking good but still "dark monitor screen" .
Sometimes documentation can be useful to "find" an atypical error. It's good having hard to find documentation ,just in case .

Don't get me wrong I don't argue about usefulness of documentation. Using schematics or repair guides helps to repair fast and well.
I've meant absence of documentation for the exact device or chip shouldn't be an obstacle to start repairing.
Many damages can be find scrutinizing a board or measuring main power rails and so on.