I had an IBM 5160 not too long ago, 2023 was it? It was a fun little machine with 384KB of RAM, a XT-CF in place of the original hard disk, a V20, and a Hercules graphics card. It just wasn't a fun enough little machine for me to really want to keep it, the thing was just a hair too weak to run anything I desired at the time while also being a hair too much to get that "original model" experience that I seek out in my retro PCs with long-running lineages. I sold the system at CCAG '23. I did get my stronger machine not long after said sale, good friend Evie passed me a 386DX40-based box for a very reasonable price, but this ain't about that. This is about going weaker.
I was browsing eBay in October of 2024, a year and four months after selling that 5160 with all its goodies and a keyboard at CCAG '23, and I saw an IBM 5150 go up for sale. It was $150 with $30 shipping. It came with a MDA, the floppy controller, some sort of 64K RAM card, and that good 'ol 63.5W PSU. The 64K card and two-screw case tipped me off that it probably had a 16-64K motherboard. A bit more than I wanted to pay but a bit cheaper than the other systems up. I was close but decided nah, distaste for the cost trumps desire, and put the phone down.
The next day I woke up seeing an offer for the thing at $127.50 shipped, contemplated it a little harded, still decided "nah", and put the phone down again.
The day after that I woke up to yet another new offer, now only $107.50 shipped. For the hell of it I offered $20 less, $57.50 for the system + $30 for shipping. They actually took it.
Pretty, eh? I think so, I love the dual-floppy look.
While waiting for the 5150 to ship to me, I started debating what I'd exactly do with the system. My first decision was that I want to keep the system pretty damn "stock", just the IBM system with whatever IBM expansion cards existed. minuszerodegrees has a pretty good list of expansion cards which I used to get ideas for exactly what I'd want in my computer. Of that list I decided I should look for the Asynchronous Communications card, the Analog Input card, any of the first three Memory Expansion boards they list (32K, 64K, and 64K/256K), a CGA.
The first setup I could think of enjoying would be the obvious "playing games" route. CGA, game port, a bunch of RAM, and a stack of booter disks.
The next idea was running a BBS. RBBS-PC runs using the MDA, two disk drives, the serial card, a Smartmodem 1200 and 128KB of RAM.
The last idea was making some sort of funny homebrew. It would be cool writing something that uses both the MDA and the CGA.
The expansions in the system when I got it.
Once the machine got to me, my first order of business was tearing the thing apart. This really wasn't too hard because the previous owner must've lost the two original screws to hold the top on, their one replacement is the wrong thread size so it just pops out with the tiniest amount of force. I do want to get two new screws that way this isn't an issue in the future, a quick search of "IBM 5150 case screw size" told me to get #8-32 x 3/8" hex heads so I'll do just that on my next hardware store trip.
The second order of business was figuring out if I had a 16-64K motherboard or a 64-256K motherboard. I knew from the pictures that I had all four banks of motherboard RAM populated but I didn't know what type, they didn't give me that angle. A quick look showed me 36 Mostek 4116s, 16-64K it is! I also figured I should look to see what BIOS ROM revision I had, U33 is part number 5700671 which they say is the second version. It apparently won't recognize anything past 544K of RAM or any sort of BIOS expansions on ISA cards. I also figured I should look to see what Cassette BASIC revision I had. I've got the set of 5700043, 5700035, 5700027, and 5700019 which means I have C1.00 installed.
The next thing to do was popping out all the expansion cards that you saw above. I just wanted to get clean pictures of them, I couldn't find any sort of reference to that RAM card online so why not put it up in case anyone else wants to see it? There's nothing all too crazy going on between the three, just the plain 'ol FDC and MDA plus that 64K card.
The last thing I wanted to check out after all that was the floppy drives. I noticed in pictures that Drive 2 didn't have an IBM faceplate and didn't look like any Tandon I had seen before. Looking at the drives in-person told me the same thing. I undid the two screws, slid it back, and checked the label - it's a Magnetic Peripherals Inc. (CDC) BR8B1A full-height DS/DD drive from June of '83. Pretty cool.
I've got the system.
I've got a MDA-compatible monitor, a real nice amber one from a Brother word processor, alongside a few options for CGA.
I hooked a 360K drive up to my Greaseweazle and wrote out a PC DOS 2.0 disk, a disk containing all the stuff for RBBS-PC, a Zork disk, and a 101 Monochrome Mazes disk.
I don't have a keyboard yet, the last thing I really require before I can get to using the system. I was going to just buy a Model F, people say they're quite the nice things, but my oh my do they get expensive. I'm also just not too much a fan of buckling springs any more, I used to love Model Ms but nowadays with most of my typing on MX Silent Reds they tire my hands out. Friend seatsafetyswitch made the joke I should just roll my own keyboard so I might just go do that for the heck of it.
I guess check back in at a later date, hopefully I'll have this thing up and running!