IBM 5100 System

[slimbob]

Hello all,

I was recently able to acquire a complete IBM 5100 system including a 5103 printer, 5106 tape drive, documentation, and tape cartridges from one of the original owners of the company that purchased it in 1978. It was used for only a year or so before being put into storage, so everything is in beautiful condition. I have powered the computer on and it appears to be operational, but have hesitated to do much more until I familiarize myself with it's operation and evaluate it's condition. I am hoping to get the system fully operational, but there are a few issues I need to address and I have some questions about the best way to proceed. I would welcome advice from anyone familiar with the 5100 line of machines.

The two tape drives are the only means to load anything into the massive 16k of memory of the 5100, and the only means of storage, so I want to make sure that there is nothing I need to check or be concerned with on these before trying to use them. I know the rubber capstans can be bad on the old tape drives, but these appear solid. If anyone knows of anything else I should check on these I'd be interested to hear.

A related concern is the tape cartridges. These are now 35 years old, and their condition is unknown. I have a few IBM supplied cartridges as well as some that were used for data. I want to try to copy the original IBM tapes to fresh cartridges if possible before I do anything else with the machine. Anyone have any suggestions or tips on doing this? I think I may be missing at least one key tape (although I have some tapes that are not labelled and it may be one of those). If anyone has backups of any of the original IBM tape cartridges, or can make copies of these for me that I could purchase I would be very appreciative. When I have the system up and running I hope to be able to provide copies of my tapes, or others, to anyone who might need them. I also have some documentation that I have not seen online. I would be happy to scan anything I have if someone needs it.

One last thing concerns the 5103 printer. This is the only printer that will work with this machine, so I need to address two issues I have found. The tractor feed for this attaches to the printer by means of two clips on each end. On one end of mine one of the clips was broken at some point. I can probably repair it, but I would like to find a replacement part. I also need to locate some small parts for the ribbon drive (roller assemblies). These would have been cheap easy to replace in 1978, but not so now. Does anyone know someone who might have any of these parts, or maybe a 5103 parts unit?

I'm sure I will run into more issues as I go, but these are my priorities at the moment. I welcome any ideas or input anyone has.

slimbob

 

[TanruNomad]

Wow, what a find. The true holy grail of portable computers. Unfortunately I know zilch about the machine other than what little I've read about it. Never seen one in person. From what I recall, it came with only 1 tape drive so the second one must be an add-on? Should be lots of fun learning about the machine. Good luck and take pictures!

 

[barythrin]

Do you have any trouble shooting guides? I'm of course hypothetically speaking but sometimes there were good notes on maintenance for folks who supported them. The problem of course being those were primarily business machines so I'm not sure how much they would ever support an end user (non IBM contracted) opening up the system. Certainly envious though! You should take some pictures Some folks scavenge parts from other printers (usually found local and cheap/free) but finding matching parts may be a bit more difficult.

 

[slimbob]

Wow, what a find. The true holy grail of portable computers. Unfortunately I know zilch about the machine other than what little I've read about it. Never seen one in person. From what I recall, it came with only 1 tape drive so the second one must be an add-on? Should be lots of fun learning about the machine. Good luck and take pictures!

Yes, I was incredibly lucky to find this thing on Craigslist listed as an IBM 2100. It didn't sound familiar so I checked out the ad and pretty much soiled myself when I saw a picture of what I knew right away was one of the early IBM "portable" computers. I have seen these for years but never gave owning one a second thought.

The 5100 has an internal tape drive, but an auxiliary tape drive unit was available (5106) that allows transferring data directly from one drive to the other. With one drive, if you wanted to copy an entire 200k cartridge the computer would start loading the data into memory, but with only 16k of memory you would have to write to the destination cartridge in a number of consecutive tape switching operations. It seems so ridiculous now, but this was state of the art at the time. Later versions in the 5100 series (5110 and 5120) had the ability to use 8" floppy drives, but I don't believe that the 5100 will work with those.

I have some pictures and will take more as I work with this. I haven't posted on here much so I will have to figure out how to post pics. I'll try and get some on soon.

 

[slimbob]

Do you have any trouble shooting guides? I'm of course hypothetically speaking but sometimes there were good notes on maintenance for folks who supported them. The problem of course being those were primarily business machines so I'm not sure how much they would ever support an end user (non IBM contracted) opening up the system. Certainly envious though! You should take some pictures Some folks scavenge parts from other printers (usually found local and cheap/free) but finding matching parts may be a bit more difficult.

barythrin, I have maintenance manuals for the machine that cover each of the units. There is quite a bit of maintenance and diagnostic information, but I have seen some of this available online. I do have some things which I have not seen but I need to catalog what I have. The material is definitely intended for use by IBM service personnel, but it's very detailed and clear. The system is completely different than anything I have ever worked with, so I am very glad that the documentation came with it.

 

[slimbob]

Here are a few pictures of the 5100 (if I am doing this right. I will take more as I go.

 

[angel_grig]

Wow!Excellent finding!It is in excellent condition!

 

[slimbob]

Wow!Excellent finding!It is in excellent condition!

Yes, it was stored for many years and of course was dusty and had the usual coffee cup ring on the top, so I have given everything a good, basic, exterior cleaning and aside from a minor scrape here and there it is in great condition. I have opened up the tape drive and the printer and both have the dust, but probably less than the computer I use every day. The only thing that didn't age well (that I am aware of) is the foam sound deadening material that IBM used on the inside of the printer enclosure. The foam had fallen away as it deteriorated and was not saveable (it just crumbled at the slightest touch), so I measured what was left and removed it. I should be able to find a good replacement material and I will replace it when I have a chance.

I have not opened the computer yet, but I know that a similar foam was used in a few locations on the inside. I'll wait and see, but chances are the foam inside the computer has deteriorated as well. I don't like the idea of replacing anything original on any of my old computers, but I don't want anything floating around in there getting into the fan, or blocking vents, etc. I'll just have to take a look and see.

 

[TanruNomad]

Very nice condition and complete too! Worth a couple thousand probably. It's one of the few computers I continue to search for on CL just randomly every now and then in the small hope of getting one. They were made for quite a few years, but still seem to be quite rare. Is the display limited to just that monitor or can it be connected to an external monitor or terminal? And does it use a variant of BASIC? Please keep us updated if you start running software for it.

 

[slimbob]

Very nice condition and complete too! Worth a couple thousand probably. It's one of the few computers I continue to search for on CL just randomly every now and then in the small hope of getting one. They were made for quite a few years, but still seem to be quite rare. Is the display limited to just that monitor or can it be connected to an external monitor or terminal? And does it use a variant of BASIC? Please keep us updated if you start running software for it.

The 5100 was made from 1975-1978. I believe the later models were sold until 1982. There is a connector on the back (I forget the proper name for it but it is common) to which you can connect a monitor or a TV set as an external monitor.
Mine is BASIC only. Other models could use APL as well. The BASIC is recognizable as BASIC, but it's not the BASIC that I remember. I have a binder with a workbook and 3 tapes dedicated to BASIC instruction which I will try and put to use.

 

[TanruNomad]

The 5100 was made from 1975-1978. I believe the later models were sold until 1982. There is a connector on the back (I forget the proper name for it but it is common) to which you can connect a monitor or a TV set as an external monitor.
Mine is BASIC only. Other models could use APL as well. The BASIC is recognizable as BASIC, but it's not the BASIC that I remember. I have a binder with a workbook and 3 tapes dedicated to BASIC instruction which I will try and put to use.

Oh cool. I wonder if it's a composite video output or something. That would be sweet and convenient. 1975 BASIC, that's some old school BASIC! I use Applesoft BASIC all the time these days, the only other variant I used to use as a kid was VBASIC. I remember I made a silly text adventure game with Martians and such. I think I still have it on an old HD in storage somewhere

 

[slimbob]

A Little progress

A Little progress

I opened the 5100 up and looked inside for the first time today and the condition of the interior is pretty amazing for a 35 year old machine. I took the cover off and took some pics, and I am posting some. I should probably check power supply voltages, but today I just wanted to take a peek.

I also partly disassembled the 5103 printer because some small parts (drive rollers for the ribbon) were missing and I wanted to see if they had dropped down into the printer. I didn't find them, but while I had the machine apart I blew out some dust and cleaned and lubricated some things. I'll have to fabricate some replacement parts for the ribbon drive. I've got new ribbons coming as well.

I need to take a look at the tape drives and do a little cleaning as well as check the capstan rubber. They look pretty good, but it wouldn't be surprising if they had deteriorated over the years. I might take some measurements just in case.

slimbob

 

[Qbus]

It sounds like the height of stupidity but about fifteen years ago I sold my 5100 system on EBay for a box full of money. Back in the early eighties I use that system to learn Basic programming and at one time had two of the systems up and running, think around 86 or so sold one for $50 at a Hamfest in Baltimore that was one of the Basic versions only and kept the Basic/APL version only to sell that in the nineties. The foam was a big issue with them because it deteriorated and got all over everything. I just vacuumed all the foam out and the systems ran fine without it. I did have to repair the power supply once because of a failed filter but they were straight forward designed DC to DC converters unlike all the cards in the system that use those strange little square IBM proprietary chips. I also had the async serial card and the external printer but recall that the printer was huge, heavy and required a special ribbon and this was back in the eighties so have no idea where you would find one today. The printer had the world's weirdest connector being three DB-25 or something like that arranged in a triangle with a box on the end of the cable that was huge. At the time I had some friends who worked for IBM so they set me up with ribbons and spare tape cartridges. From what I recall loading programs from tape or to tape was straight forward being the load command in basic followed by the two digit track number and then just run, or you can toggle in basic programs and use save with assigning a new track number. The display is a standard monochrome video output that will work with any monitor as long as it’s an old legacy analog video monitor and not a computer monitor, lot like the old Apple 2 output only monochrome. I never had any issues with the tape drives but this was over twenty years ago and if I had a system today would remove the drive, clean and oil all the bearings and look real carful at the capstan shaft. Don’t remember if the roller was in the cassette or rose up into it but there is any sticky stuff on that and it will eat the cassette. When the drive is running the tape moves real fast in the cassette so everything has to be clean. The drives are also loud compared to modern technology so the first time it works it will probably scare the hell out of you. Don’t know if I remember this correctly or not but from what I recall if you remove the one screw in the front of the card rack and the other on the front of the power supply the whole system opens up like a book and somehow I recall being able to operate it that way and view the operation of the tape drive.

 

[slimbob]

It sounds like the height of stupidity but about fifteen years ago I sold my 5100 system on EBay for a box full of money. Back in the early eighties I use that system to learn Basic programming and at one time had two of the systems up and running, think around 86 or so sold one for $50 at a Hamfest in Baltimore that was one of the Basic versions only and kept the Basic/APL version only to sell that in the nineties. The foam was a big issue with them because it deteriorated and got all over everything. I just vacuumed all the foam out and the systems ran fine without it. I did have to repair the power supply once because of a failed filter but they were straight forward designed DC to DC converters unlike all the cards in the system that use those strange little square IBM proprietary chips. I also had the async serial card and the external printer but recall that the printer was huge, heavy and required a special ribbon and this was back in the eighties so have no idea where you would find one today. The printer had the world's weirdest connector being three DB-25 or something like that arranged in a triangle with a box on the end of the cable that was huge. At the time I had some friends who worked for IBM so they set me up with ribbons and spare tape cartridges. From what I recall loading programs from tape or to tape was straight forward being the load command in basic followed by the two digit track number and then just run, or you can toggle in basic programs and use save with assigning a new track number. The display is a standard monochrome video output that will work with any monitor as long as it’s an old legacy analog video monitor and not a computer monitor, lot like the old Apple 2 output only monochrome. I never had any issues with the tape drives but this was over twenty years ago and if I had a system today would remove the drive, clean and oil all the bearings and look real carful at the capstan shaft. Don’t remember if the roller was in the cassette or rose up into it but there is any sticky stuff on that and it will eat the cassette. When the drive is running the tape moves real fast in the cassette so everything has to be clean. The drives are also loud compared to modern technology so the first time it works it will probably scare the hell out of you. Don’t know if I remember this correctly or not but from what I recall if you remove the one screw in the front of the card rack and the other on the front of the power supply the whole system opens up like a book and somehow I recall being able to operate it that way and view the operation of the tape drive.

Are you in Maryland? I'm in Frederick- bought this near Baltimore. I wish this was the APL/BASIc version, but hey, I'm not complaining. The foam was only an issue in the printer. It seems ok in the 5100, but I'm sure it's extremely fragile. I'm going to leave it alone unless I really have to play with it. The foam under the cards in the backplane looks ok, but if I swing that gate up I'm sure it will rip right out.

I don't have the serial card in mine. Yes, the weird connectors are foreign to me. I understand that they were called "BUT" boxes, for big, ugly, thing. They are the only way to connect anything to this machine so whatever you want to attach to this machine has to have that weird connector. I have one extra connector, but it may also be some type of termination device- I need to check that out.

I found ribbons, as well as some old stock tape cartridges and I will definitely take a good look at the tape units before I start messing with them. I have a stand-alone drive, so I can take the cover off of that and check out whats going on. It will take me a while to feel comfortable with the way this thing operates- it's definitely not what I am used to. But it should be fun learning!

 

[Qbus]

I am located over on the eastern shore in Salisbury. If you have not opened up the inside of the system you may want to do that first and clean out what's left of the foam that was between the cards and the case. Also this will allow you to see and pull the cards and clean them off, it will be a sticky mess and also be cretin to make a drawing of the location of each card and cable before you pull things. Been a long time but think there was a full with processor card, a full size I/O control, maybe a couple ROS (ROM) cards that are half with that have a plastic frame that fills the full with bay and at least two half with 8K memory cards and a full with display card. May be one or two others in there, been a long time.
The foam on the bottom was there to keep the card from coming out in shipping or something and as long as you're not throwing the system around don’t think any of the cards will drop out. If you have never seen sixties or seventies style IBM construction it will be a real lesson because there design was nothing like anything used in a PC and more along the lines of things like an IBM 360 maybe that was the last of the line to use that style of construction because by that time everyone else was using off the shelf components and standard TTL and CMOS they were still using their own style of cards, connectors and integrated circuits. From what I recall there are some 74/4000 series devices but mostly those postage stamp gray IBM things, so that system is more related to the mainframe systems and only a distant relative of the 5150 and the modern PC.
Once you get it running I would recommend using an external video monitor because that’s easier to see then the little five inch display. After starting the system you will see it run its diagnostics and then post a "READY" display, at least if you boot it in basic. Think they used something like IBM System 3 Basic and if you have ever used anything like GW Basic you will find it just about the same. You don’t need to load a tape or operating system or anything like that, just start the system in Basic and its ready to go. The APL version supposedly runs the same instruction set as the 360 mainframes and have always assumed those systems were for developing and debugging software on mainframe systems.
Those systems are getting a bit old now and would be interesting to see your progress in getting it up and running. Let me know if threes anything I can do to help.

 

[eeguru]

That's a very nice machine you found.

What's the difference in the BASIC vs APL vs BASIC/APL versions of the 5100? It is a logic difference or just a ROM load. Maybe you can have your cake and eat it too.

 

[slimbob]

I am located over on the eastern shore in Salisbury. If you have not opened up the inside of the system you may want to do that first and clean out what's left of the foam that was between the cards and the case. Also this will allow you to see and pull the cards and clean them off, it will be a sticky mess and also be cretin to make a drawing of the location of each card and cable before you pull things. Been a long time but think there was a full with processor card, a full size I/O control, maybe a couple ROS (ROM) cards that are half with that have a plastic frame that fills the full with bay and at least two half with 8K memory cards and a full with display card. May be one or two others in there, been a long time.
The foam on the bottom was there to keep the card from coming out in shipping or something and as long as you're not throwing the system around don’t think any of the cards will drop out. If you have never seen sixties or seventies style IBM construction it will be a real lesson because there design was nothing like anything used in a PC and more along the lines of things like an IBM 360 maybe that was the last of the line to use that style of construction because by that time everyone else was using off the shelf components and standard TTL and CMOS they were still using their own style of cards, connectors and integrated circuits. From what I recall there are some 74/4000 series devices but mostly those postage stamp gray IBM things, so that system is more related to the mainframe systems and only a distant relative of the 5150 and the modern PC.
Once you get it running I would recommend using an external video monitor because that’s easier to see then the little five inch display. After starting the system you will see it run its diagnostics and then post a "READY" display, at least if you boot it in basic. Think they used something like IBM System 3 Basic and if you have ever used anything like GW Basic you will find it just about the same. You don’t need to load a tape or operating system or anything like that, just start the system in Basic and its ready to go. The APL version supposedly runs the same instruction set as the 360 mainframes and have always assumed those systems were for developing and debugging software on mainframe systems.
Those systems are getting a bit old now and would be interesting to see your progress in getting it up and running. Let me know if threes anything I can do to help.

My kids went to Salisbury University so have been ouy that way many times.
I might consider opening the thing up, and like you said, I am sure the foam will need to go, but a suitable replacement wouldn't be hard to find. Is here a reason you think I should pull the cards? They definitely are interesting, but I am loath to play around with too much unless I need too. I know that I need to remove the controller cards for the tape drives to access the heads and check out the capstans.

I have started the machine up once and it came up with the "READY" prompt, so I know it is functional to good degree. I'm not familiar with System 3 Basic, but the commands look fairly standard. It's the tape usage commands (like PATCH and COM) that I need to study. I'm just not familiar with tape drive procedures at all, so this is something that you could definitely help me with if you would be so kind. I will study the docs I have and see what makes sense and what is still fuzzy, and I may very well have some questions for you. Thanks for the offer.

You could probably address the question below concerning APL and Basic. An IBM engineer who actually worked on this system and programmed for it told me that APL was a lot more fun to work with. But he had a mainframe background. He indicated to me that my machine could be updated with the proper cards and a switch and cable (which would normally have been on the front panel). I probably wouldn't alter anything on this machine, but if I found the cards and could rig a switch I would consider doing it just to be able to play with APL. It looks a little daunting to me, but it's been around since at least the early 60s, so it would be interesting to check it out. I don't expect that those cards are very common these days, so it's something I probably won't even have to think about.

I'll check back in with any progress- got the tape cartidges yesterday.

slimbob

 

[Qbus]

If you got the "READY" prompt your ready to go, you can toggle a basic program directly in from the keyboard. Just do something stupid like:

10 REM NUMBER THING
20 PRINT" ENTER THE NUMBER"
30 INPUT X
40 X=X+5
50 PRINT
60 PRINT X
70 PRINT
80 END

Then enter "RUN"

That will take whatever number you enter and add five to it and then print it. The tape drive commands are straight forward with "SAVE" and then the number of the track you want to save to in a two digit form, so to save the program that you just entered on track 2 you enter "SAVE 02" and to recall its just "LOAD 02" from what I remember whenever you loaded a program it overwrites whatever is in memory at that time so when you enter "RUN" the program executes. I was never that good at programming but I remember the IBM Basic programming course tapes had the ability to load a main menu and allow you to select tracks or lessen and return you back to the main menu. Don’t know how they did that, maybe had a routine to load track 00 and run at the end of all the other tracks on the tape.
There are two different sets of ROS cards. One card has the ROS for Basic and the second card had the ROS for APL. The ROS cards had the operating system or microcode on them directly and think there were no provisions for loading or getting to the microcode in the system. The system with both Basic and APL had a switch that selected what set of ROS would be loaded. I am not cretin and am in no way a expert on these systems so may be completely wrong but think there may have been a additional ROS card that held microcode for diagnostics and hardware configuration but would not swear to it. Just thinking back now and not cretin what ROS stands for, maybe just IBM speak for ROM? something like how they call the CPU just the "controller" another weird thing about that system is it gives you the ability to look at the registers directly but other than diagnostics I have no idea why they did this because the system always operates in a high level language like Basic or APL and I do not think it's possible to get to the microcode beneath.
There got to be someone around who can answer questions better than me. But if you're getting the "READY" prompt, you got all the dirt and foam debris cleared from the system and the power supply fan is working you're ready to enter and run basic programs and not need the tape drive yet. If you don’t call "LOAD" or" SAVE" the drive will just sit there and you don’t need to put a tape in the machine.

 

[slimbob]

If you got the "READY" prompt your ready to go, you can toggle a basic program directly in from the keyboard. Just do something stupid like:

10 REM NUMBER THING
20 PRINT" ENTER THE NUMBER"
30 INPUT X
40 X=X+5
50 PRINT
60 PRINT X
70 PRINT
80 END

Then enter "RUN"

That will take whatever number you enter and add five to it and then print it. The tape drive commands are straight forward with "SAVE" and then the number of the track you want to save to in a two digit form, so to save the program that you just entered on track 2 you enter "SAVE 02" and to recall its just "LOAD 02" from what I remember whenever you loaded a program it overwrites whatever is in memory at that time so when you enter "RUN" the program executes. I was never that good at programming but I remember the IBM Basic programming course tapes had the ability to load a main menu and allow you to select tracks or lessen and return you back to the main menu. Don’t know how they did that, maybe had a routine to load track 00 and run at the end of all the other tracks on the tape.
There are two different sets of ROS cards. One card has the ROS for Basic and the second card had the ROS for APL. The ROS cards had the operating system or microcode on them directly and think there were no provisions for loading or getting to the microcode in the system. The system with both Basic and APL had a switch that selected what set of ROS would be loaded. I am not cretin and am in no way a expert on these systems so may be completely wrong but think there may have been a additional ROS card that held microcode for diagnostics and hardware configuration but would not swear to it. Just thinking back now and not cretin what ROS stands for, maybe just IBM speak for ROM? something like how they call the CPU just the "controller" another weird thing about that system is it gives you the ability to look at the registers directly but other than diagnostics I have no idea why they did this because the system always operates in a high level language like Basic or APL and I do not think it's possible to get to the microcode beneath.
There got to be someone around who can answer questions better than me. But if you're getting the "READY" prompt, you got all the dirt and foam debris cleared from the system and the power supply fan is working you're ready to enter and run basic programs and not need the tape drive yet. If you don’t call "LOAD" or" SAVE" the drive will just sit there and you don’t need to put a tape in the machine.

Thanks for that info. I have seen simple basic programs run on one of these so I know I don't need the tape drive for that. My interest in the drive protocol is mainly because I would like to copy the original tapes I have (like the three basic programming course, which I have). But I may fire up the 5100 and play with it first and deal with the tape drives as a separate issue. If I do maybe I can do a little video of how it goes and post it on here.

Thanks again for the info!

slimbob

 

[Qbus]

I tried but cannot remember myself and just did a little bit of looking but did not find anything. Is that transport using cassettes that are only driven by the capstan? And internal gears in the cassette that drive the two reels together? Or is there some way that the reel tables are driven by an external motor? The more I think about it somehow think the only thing that moved the tape was the capstan and somehow the reels were locked together.