IBM 5100/5110 Sources


I am by no means a “professional collector.” I’m an engineer with an interest on the technical workings of these “now ancient” systems, but also a kind of historian interested in the humble beginnings of the “digital information age.” The idea of interpreting “0” and “1” to conduct processing, with the instructions passing at a set clock speed, stems from the 1930/1940s (at least, applying this concept with electronics paired with evolving the application of Boolean-logic). But it wasn’t until the 1970s that computers were “domesticated” enough to be brought into homes, as a practical appliance to both technical and non-technical users. My daughter and I made a mural about this (see here).

NOTE: “technical” in this context is meaning focused more about the inner workings of the system, the voltages involved, instruction set and various interconnections. “non-technical” meaning just wanting to use the device to get some specific task done (e.g. writing and editing a letter, data/record entry, calculating material costs).

The IBM 5100/5110 came to me purely by chance, a matter of “being in the right place at the right time” since they weren’t actively being sought.

The IBM 5110 (#1)

I obtained my first IBM 5110 Type 2 at VCF West in August 2021, which has a “consignment shop” during the events. I noticed it sitting by itself on a desk, without much attention being paid to it. Maybe because the case was a little dirty, or maybe because it was a “BASIC-only model.”

I noticed the “IBM 5110” tag at the top and had to do a double take, while in my head thinking “that’s really old!” Curious if it still worked, like a kid, I plugged it in and powered it on. In hindsight, I should have asked around first, since I later learned that’s not quite the proper way to handle 40+ year old rare equipment. But the outlet was right there! Fortunately, the system powered on, indicated 32KB of memory, and I could enter and run a BASIC program. One trick was the system has no “double quotes” (as it typically used in BASIC to print strings), but I quickly deduced that the only viable alternative was a single-quote (which ended up being on the “K” key). Another trick was that if you type an error, the system beeps and flashes where your error is at. There is no way to proceed, but I then figured “ATTN” meant attention (sort of like what later became ESCAPE on more modern keyboards), and indeed pressing that stopped the flashing error and lets me fix the mistake.

The system was older than me, yet intuitive to use. And aside from some debris on the screen and an obvious “used condition,” it was in decent working order. I tried to put the system out of my mind, since being on travel there was no practical way for me to bring it back home. And yet, the next day I came back to VCF early to make an offer. In fact, too early, since its owner wasn’t around. The consignment staff helped track down a phone number, and thankfully Dale Luck (a retired IBM engineer) answered his phone. He said another offer had been made and was supposed to be paid the day before, but hadn’t yet. I mentioned how I was on travel with family and didn’t have that much time to stay at the museum that day. So, he agreed that if it wasn’t sold that day, he would call and accept my offer (plus work out shipping details).

I was half hoping he wouldn’t call, and I’d accept fate that the 5110 was destined to go somewhere else. But, late in the day, he did call. The annual VCF event was ended and the original person who made an offer didn’t arrive back. Dale and I negotiated on the shipping, and I still get a laugh that he shipped it in a box for a toilet! I appreciate fate leading me to finding this system, meeting its owner, and having it successfully shipped half-way across the country.

NOTE: September 2022 I removed the CRT of this unit for inspection. In doing so, I realize the apparent “screen debris” was actually just on the “screen protector” itself (and not the CRT glass). This “screen protector” is also a kind of anti-glare material that sits right in front of the screen. This was easily cleaned, making the center of the screen appear much clearer. This also suggest that the CRT had been repaired or replaced earlier in the systems life.

The IBM 5110 (#2)

An acquaintance online had come across two IBM 5110’s. Both were missing keyboard and power supply. But one of them was a Type 1 model (with the tape unit). We negotiated a price with shipping, and they arrived intact. However, the display card on one of these was not functional.

Between these two for-parts systems, I can get one working “extra” IBM 5110. The internal tape unit still is not working (it is getting power and responds to REWIND, but the READ/WRITE head doesn’t appear to be working). In addition, the rollers on the internal tape unit are missing, which maybe is causing an alignment issue with the tape head. Still, these have been very useful for-parts systems in exploring the inner workings of these IBM systems (such as developing the USB/serial keyboard adapter and PSU replacement). That is, I can tinker with these spares, while keeping pristine #1 intact (or as a confirmed reference on how signals should go).

The 5100

During the summer of 2022, two IBM 5100’s appeared on eBay. While I wasn’t actively looking for even more equipment, several contacts made me aware of the listings.

The first was a “decked out” APL+BASIC Type 1 (C12) model that appeared to also have the “Expansion Feature” (async. I/O). The overall condition was good (clean case), CRT screen worked, and had 32KB RWS. The unit sold for over $9500 (located in the North East, near New York).

The second, a few months later, was a BASIC Type 1 (B12) model also with 32KB RWS and had an IBM 5106 external tape unit. This was an estate sale, where a grandfather had passed away. The unit was shipped from Winnipeg, Manitoba, Canada, but has stickers indicating it was used in a hospital in Fort Frances, Canada (right along the Ontario/Minnesota border). Long since retired and thankfully kept out of the sun. This one was $4000.

BELOW: La Verendrye General Hospital, Fort Frances, Ontario 0262 (this same label on the matching IBM 5106 external tape unit) [here]

I did not get the APL version. But I want to note the following: I had the impression that during this summer of 2022, a more-than-usual number of collectors were selling pieces (e.g. original Apple-1 board). Possibly this was due to more-than-usual economic uncertainty (rising inflation, major increase in housing costs, and Ukraine incident). I’m also aware that because of personal health issues (or the health of a spouse), some collectors are obliged to “reduce the size of their collections.” I say this based on phone calls and discussions with several museum or collection owners. And consider, most of the original owners of this 45-year-old equipment (in 2022) would now be in there 60-80’s. The last generation who knew a world before personal computers and world-wide digital communication is at hand.

Thankfully, the B12 IBM 5100 model that I received is fully functional, including both the internal and external tape deck. The unit had its original “black goo” and keyboard shroud (which are prone to deterioration), which verifies it is all original parts. The only issue was that the internal tape deck needed a slight re-alignment for the contact switches.

NOTE: In early 2022 there was a “3rd” IBM 5100. A forum contact had helped me track it down to a seller in Florida. This was also a “decked out” IBM 5100 (meaning “top of the line” APL+BASIC model with 64KB RWS), possibly with both the Serial I/O and expansion feature. It had no 5106 external tape unit, but it did have the leather case that IBM sold with these units. This at least confirmed such a thing existed (form fitted perfectly to the IBM 5100 case). Unfortunately, the seller was only interested in local pick up and I was not able to accommodate that in time.

I enjoy stories from actual original users of these systems. Or if you have one, just give a shout out, since we truly don’t know how many of these are left in the world. I consider them about as rare as the Sol-20 (from 1976), since a report from CORE indicates that not over 30,000 units were ever made. I am looking for a keyboard or display card, or any comm/serial card, if anyone has one in poor condition for parts.

contact dot steve dot usa at gmail dot com

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