32 votes
Accepted

Why did Socket 3 have more pins than needed for the 486?

The extra pins were forward-planning, on both Socket 2 and Socket 3. Most of the extra pins are used for power (Vcc) and ground (Vss), which is useful to provide more power to a CPU. The other pins ...
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25 votes
Accepted

What causes the traces to wrinkle like this and should I be worried

They were most likely wrinkled like that from the start, due to the way they were manufactured, and thus you should not be worried. Until the mid-90s, boards often went through an HASL, or "hot air ...
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  • 20k
20 votes
Accepted

What was the first multiprocessor x86 motherboard?

Preface The question is a bit unclear(*1) about the margins set regarding: Must it be a single motherboard or do separate assemblies qualify? Must it be PC-compatible or does any x86 system qualify? ...
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  • 166k
18 votes
Accepted

32-bit PCI riser cards: different types?

I have used these passive PCI risers quite a lot and some of them need their "fingers" to be cleaned with something like isopropanol before they work properly. Especially on the top photo ...
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  • 545
17 votes

Identifying motherboard and CPU

I inquired about the CPU over on ee.se. The chip appears to be an AMD Am386DX-25. Compare the lower printed number (107M7NX and 107M7NZ), the fonts used, the logo at the bottom-right, and the laser-...
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  • 8,787
15 votes
Accepted

Small RAM 4 KB on the early Apple II?

Most of the reference material for the Apple II that I have seen refers to the 4116 RAM chip which held 16x1 kbit. Jup, at the time the Apple II really took off, 4116 chips had already dropped to ...
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  • 166k
13 votes

Identifying motherboard and CPU

Apart from the unrecognized branding on the CPU (ceramic; upper-right in photo) chip, this appears to be a bog standard ISA '386 motherboard, probably running at 25 MHz. CPU looks like the right ...
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  • 56.4k
13 votes

What was the first multiprocessor x86 motherboard?

If you’re looking specifically for motherboards directly supporting multiple x86 CPUs, in a multiprocessor configuration, and available for purchase outside the system they were designed for, a likely ...
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11 votes

How can I tell if my old PC supports > 137 GB hard drives?

Very briefly: The way harddisks are addressed changed over time. Originally, you'd specify cylinder/head/sector (CHS), then it switched to logical block addresses (LBA), and the commands for those ...
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10 votes
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Is there a way to trick my 386SX laptop into thinking there's a floppy drive installed?

The standard algorithm to probe for floppy drives (and tell 1.2MB drives from 360KB drives) is patented by IBM and yet cloned by most BIOS manufacturers. There were litigation lawsuits against Award ...
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10 votes
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What is this socket for in 386 notebook motherboard

Well, it could easy be a socket for a 387 type FPU. Size and number of pins would fit a 387 (or some pin compatible Cyrix FastMath) as PLCC carrier. On the other hand it's rather unusual to place it ...
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  • 166k
8 votes

What causes the traces to wrinkle like this and should I be worried

This is actually a comment, but images cannot be inserted in a comment, so I wrote an "answer", just to point out that this kind of trace looking is already known in other computers, like the ZX ...
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8 votes

Why did Socket 3 have more pins than needed for the 486?

Socket 3 did not have more pins than needed. It was designed to support the Pentium OverDrive CPUs that Intel released in the mid-1990s. These CPUs could have up to 237 pins, while the Socket 3 ...
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  • 56.4k
8 votes

Small RAM 4 KB on the early Apple II?

The following information comes mainly from pages 70-72 of the Apple II Reference Manual, 1979 edition. The Apple II had three rows of eight sockets for DRAM: rows C through E from front to back. Each ...
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  • 20k
7 votes

CPU slaves on a PCI card to retrofit single processor to multiple processors. Any ideas how?

how I can add additional slave processors (and possibly RAM) to this system through the mainboard's PCI card slots While DMA works through PCI, this is not practical to sustain to have additional ...
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  • 20.9k
6 votes
Accepted

Can you help me identify this AMD 386-DX40 motherboard?

Not a full identification, but a hint from the chipset: It's an Acer (ALI - Acer Lab Inc) M1429, a somewhat late (1993+) ISA/VLB chipset for 386 and 486 systems. South Bridge is M1431 of the same ...
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  • 166k
6 votes

How can I tell if my old PC supports > 137 GB hard drives?

That BIOS screen clearly says that it detects the drive as roughly 8 GB. The parameters say 16383/16/63 as so this BIOS cannot detect or provide the extended disk services that would allow the drive ...
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  • 16k
6 votes

Identifying motherboard and CPU

Going by pinout and socket type it's a pretty generic 80386DX (*1) board based on the VIA FLEX I chipset (SL90xx). Probably 1990/91ish. It would need a better set of photos - especially of the ...
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  • 166k
5 votes

Award BIOS error code meaning

Found it! It was the CPU voltage setting, and the onboard VGA had to be disabled too, for some reason it didn't detect the VGA card. It turned out to be a little tricky. Now it works!
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5 votes
Accepted

CPU slaves on a PCI card to retrofit single processor to multiple processors. Any ideas how?

CompuPro did this in the olden days, with 8-bit and 16-bit CPU slave cards with a 16-bit or 32-bit main CPU. But there were a few differences from what you are suggesting: Each CPU had its own RAM. ...
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5 votes

What was the first multiprocessor x86 motherboard?

If you expand the criteria to include systems where the two CPUs are not on the same circuit board, the Intel ISBC 86/12 from 1979 is a Multibus-compatible single board computer. Later, the Compaq ...
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4 votes

What was the first multiprocessor x86 motherboard?

The DEC Rainbow (1982) was built with two CPUs on the motherboard. One was an 8088 and the other was a Z80. It could run 8 bit CPM, 16 bit CPM, or MS-DOS. When running MS-DOS, the 8080 was used ...
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  • 4,450
3 votes

Small RAM 4 KB on the early Apple II?

Original Apple II Rev 0 with 4K memory select blocks and 4K memory chips also pictured is an original Datanetics keyboard.
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3 votes

What was the first multiprocessor x86 motherboard?

Does an Apple II motherboard count? Back circa early 1981, I used a design similar to that of the Z80 Softcard to prototype an 8088 softcard that could do asymmetric shared memory multiprocessing ...
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  • 7,444
2 votes

Asus SP97V motherboard not powering up

There are various things that can cause a motherboard to behave that way. Two examples include: A Failed RAM Socket I've observed those symptoms with two different ~3GHz ATX-era boards (One ASUS M2N-E ...
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  • 3,743
2 votes
Accepted

Rationale for almost heatsunk TO-220 packages on C64 motherboard

Some points that came in as comments support that this is likely due to a "just in case" design that would allow for heat sinking the packages through the motherboard if the need should ...
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  • 4,090
2 votes

IBM PC 5150 motherboard labelling

AFAIK there is just one 14.318MHz crystal (not an oscillator) on the 5150 motherboard, right next to the 8284. It’s a flat metal component with two leads coming out of it from one side, probably ...
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