MyOldPCS

This board based on 2 National Semiconductor's INS8250 ics.

EC7978 is a IBM XT compatible PC from late Soviet Union epoch. Few days ago i got set of the electric boards without a case. And here is first one - EC7978.0003-002 memory board with: - 18 TM41256 (256k x 1) - 18 КР565РУ5Г (64k  x 1) So total capacity should be 512kb + 128kb = 640 kb 

Do you know why this board is so unusual? Usual SIS 496/496 chipset, AT power, PCI and ISA slots, 2 ide channels - same as on 99% such 486 motherboards. BUT - you will not find any user's manual on it. Seriously, for several weeks I tried to find information on this board. The board works perfectly with AMD/Intel 486 DX/DX2 processors. But everything else like DX4 or Cyrix processors does not work correctly. And finally yesterday i found manual at the  www.phantom.sannata.org . Here is links: images.rar Google Drive document

From the beginning this motherboard worked, at least it starts and shows POST screens. But also it shows multiple CMOS errors, so i was unable to boot it from hard drive. After few minutes i've found that i cannot change anything in BIOS Setup. Some options just not changing, some options could be changed but after restart everything reseted to default values. This is a clear symptom of dead CMOS battery. We have BR1225 soldered on the board. And of course i don't have replacement battery. But sure we can use some workarounds here. There is external battery connector near the BR1225. So all that we need is to find some new 3v lithium (CR2025 in my case) battery, few dupont connectors and a heat shrink tube. Only after that i was able to edit BIOS date/time and enter hard drive settings. I'm worrying now. Right now I should able to boot from hard drive, but what is this: Yeah, looks like we have SIMMs with ECC bit (9-chip modules). For such case i...

I don't know what brand it is. Probably someone can identify it. Here is few labels: 55.40901.0313250488C PL060520 Let's see what we have here: - CPU NG80386SX-25 from Intel - FPU 3C87SX-25 from IIT - 8 SIMM 30 sockets, right now installed 4 x 1Mb modules I've never saw before branded 386 branded motherboards. And i was surprised that it has so much integrated peripherals: - chipset Acer/ALi M1409A with FDD/IDE controller - perepherial controller Acer M5105 - Oak technology OTI077 VGA video controller - video RAM 4 x Toshiba TC514256AJL-70ms chips, so totally here is 512Kb video memory, also there is present ability to add more additional chips. - 1 parallel port, 2 rs232 ports. - PS/2 key/mouse ports In future posts i'll try to connect old IDE hard drive and boot MS DOS. UPD from 2022 Link to the  BIOS dumps

Laptop from the beginning of the 90th, I've got it few days ago. It has: - Intel 80386 SL 20Mhz CPU - 2048 Mb RAM - build in 3.5 1.44Mb floppy drive Ports: - VGA/Serial/Parallel ports - Kycon 3-pin power connector - 2 ports that are looks like PS/2 Also there should be battery and 44-pin IDE 2.5 hard disk, but not in my case.