Let's overclock and improve this old 286 motherboard

Fantastic conversion! I converted simm modules to SIP by using "turned pin" style male-male pin headers. They're pretty easy to solder on, they're the correct pin pitch, and they mate perfectly with the turned pin style female sockets on the motherboard.. What's easier though is you can just stuff the raw simm sockets in to the sipp headers. No need to solder or anything. If the spacing is right just stick 'em right in and they work. Granted de-soldering the old sockets and putting the headers in proper is better but the easy way works in a pinch. Also nice this motherboard with those "3 chip" modules. Older 286 boards often only post with the "9 chip" sort.

To make a SIPP, put the pins in a strip of female header, butt it up to the simm and drag solder them down. Takes about 40 seconds a SIPP when you get practiced. Alignment is perfect. Works when SIMM conversion of the mobo is hard or impossible.

Looked in an old computer shopper 1992, several sellers have SIMM memory listings with a line that says: ” SIPP $5 more per module”

8mb of RAM on a 286 would have been an insane amount, and 16mb was a pipe dream. As a kid my jaw would have dropped to the floor if I saw that much in a system. Most of us had 1mb, or 2 if you were lucky.

You can certainly make use of the thin solder in a pinch, just twist together several strands

286 Motherboards are so nostalgic!

I've added just round pin strips and soldered them on simm. The one you can use on breadboard or wherever. Worked beautifully.

Back in those days, I used to remove the pin and convert SIP to SIMM, they're same thing just SIMM socket is more expensive, price of SIP and SIMM just a few USD, when you make a lot of these those metal pins just cost human labor, at those days is not that expensive.

My guess would be that that first oscillator location is for a separate clock for the FPU.

I swapped the 8 SIMM sockets on a Macintosh IIcx recently. They were the crummy plastic ones and all the tabs had snapped. It was quite tricky getting the sockets, I also used a combination of hot air with a desoldering pump. Definitely something I don't want to be doing on a regular basis 🤣

It might be my bad recollection but I seem to remember in your second channel, in a video about a box of random junk, was an industrial equipment board containing a "Make-it 486" CPU upgrade for 286. Assuming it's not my memory playing tricks, you need to test it out on this motherboard!

Happy to see the plexus im in the background

The 286 was a real step up in capabilities but they were quickly eclipsed by the 386. I had a 286 system that I eventually jacked up to 2 MB and 12 MHz. It was an awesome DOS/Windoze machine. And I justified trying dual boot Linux on my 386 machine having the 286 as a backup in case I screwed things up on the 386. I did have to heat sink the 286 and 287 for the overclock. They ran HOT at 12 MHz.

SIPs soldered directly to the board are hell. I've pulled a bunch of SIPs from industrial controller boards. The solder used to mount the pins must have a much higher melting point than the solder used to mount them on the board. I suspect there's some silver in there. Excellent episode, full of technical tips. 👍

I have another idea for the SIPP/SIMM conversion dilemma. Take some single SIMM sockets and put SIPP legs on those! Then you can swap in any SIMMs you want, and move the "format converters" to any motherboard you want. Of course if you find the upgrading process to be reliable and not too much trouble, then by all means stick with it! Making every motherboard in your collection not suck in this particular way is certainly one way to solve the problem. It's good that you have three rolls of the "hair thin" solder, as you can put all three spools on a stick and twist the three wires together to get something that more closely matches the solder diameter you're accustomed to. When you only have one roll, you have to do it in segments which is much more annoying, although in either case you can use a drill or power screwdriver to twist the wires together, and collect the result on a new spool. It's not like any twisting stress is going to matter once they're melted.

If you unsolder the socket and solder it in, it's not a bad idea to leave a module in the socket. This means the pins are more secure in the socket. Of course I learned from Necroware. Thanks Necroware. 🙂

I'd use those generic pin sockets that you can buy for cheap to build a sacrificial jig to hold the pins in alignment while you solder them to the board, rather than having to solder them one-by-one.

Just what I needed after a long day!! Thank you, Adrian!!

I replaced my Hakko 301 with a Metcal desoldering gun. The difference is night and day. The Metcal can suck up an enormous amount of solder without needing cleaning. And it has better heat up time, stability and quick change tips in a bunch of sizes. They’re expensive new but you can find good deals used if you’re patient.

For converting the SIM to SIP you could just use a row of male-male header pins, spacing will be easy, alignment will be easy, just lay it on the SIM and solder it on.