IBM 5100 find

User avatar
inmbolmie

19 Jan 2020, 23:01

This is a recent awesome "barn find". An IBM 5100 with its matching IBM 5103 printer. At last a laptop with a proper keyboard! but you will need a very strong lap by the way as this thing weights some 23Kg :? . The printer is simillary weighted.

printer.JPG
printer.JPG (1.86 MiB) Viewed 2490 times

It is a spanish machine, but the only localized parts are the front panel switch legends, that is a good thing because localized Beam Spring keycaps are usually of a lower quality than the standard keycaps. It is a 32K RAM and BASIC only machine. With 32K the 5100 cost about $13.000 in its day or $62.000 adjusted for inflation. No idea of the printer cost but I imagine it was also substantial.

front.JPG
front.JPG (1.8 MiB) Viewed 2490 times

Has very nice "nuclear white" keycaps with BASIC sublegends. A few of them have scratches and some stems are bent, but nothing terrible. Contamination shield is disintegrated but no evidence of rust whatsoever, contrary to other Beam Spring keyboards the top plate seems to be made of aluminium, so not even a single trace of rust is visible from the top. Keyfeel is great, even by Beam Spring standard, the sound is very bassy as could be expected with the keyboard mounted in such a massive metal chassis.

key.JPG
key.JPG (1.76 MiB) Viewed 2490 times
panel.JPG
panel.JPG (1.64 MiB) Viewed 2490 times

The good news is that it seems to be almost complete, rust free and only lacking two keys (CMD and left shift) and the BASIC reference card. It came also with a rotten storage tape I doubt I can get anything from.

The bad news is that the working status is unknown after so many years badly stored. I will take some time checking the AC wiring, power supply, capacitors etc. before proper testing can begin. If anything important is broken inside I will have a very bad time fixing it.

inside.JPG
inside.JPG (3.23 MiB) Viewed 2490 times
badge.JPG
badge.JPG (1.96 MiB) Viewed 2490 times

To be continued if anything interesting comes from the restoration.

User avatar
SneakyRobb
THINK

19 Jan 2020, 23:07

Wow! Top tier. NICE FIND. Looking forward to this!

Very interesting that top aluminium plate. I wonder if the fact it was portable meant they tried to save weight, notwithstanding that 24kg size

User avatar
Bass

20 Jan 2020, 00:18

That 5100 of yours looks to be in pretty good shape considering it's a barn house find. I suggest wearing gloves when you begin your restoration as the foam underneath the card cage will most likely have turned into a nasty puddle of tar that can be very difficult to wash off.

Good luck on the restoration. A few others here (snuci and I) have also found and restored some 5100's but were unable to get them working. The ROS cards are especially prone to failure, so it would indeed be very impressive if you can get yours to work!

User avatar
Redmaus
Gotta start somewhere

20 Jan 2020, 05:52

where can I find these "barns" lol

also great find

User avatar
Chyros

20 Jan 2020, 08:03

Wow, great find mate, congratulations! :D 23 kg, damn, that's more than I thought it would be xD .

User avatar
mcmaxmcmc

20 Jan 2020, 11:55

el psy congroo

Nice find! Hopefully you can find some spare caps for the missing keys there.

User avatar
inmbolmie

20 Jan 2020, 12:24

mcmaxmcmc wrote:
20 Jan 2020, 11:55
el psy congroo

Nice find! Hopefully you can find some spare caps for the missing keys there.
For the missing keycaps I've thought about making reproductions. The left shift is easy as it is the same as the right shift. For the "CMD" I think it is the same mould than the 5251 "Enter" key but rotated 180 degrees, I have to take some measurements to check that.

andrewjoy

20 Jan 2020, 12:27

That is amazing. That thing is just built to insane standards, we simply do not get anything made to that standard any more.

John Doe

20 Jan 2020, 13:06

Is there any other stuff found to share in the gold barn?

User avatar
inmbolmie

20 Jan 2020, 13:18

John Doe wrote:
20 Jan 2020, 13:06
Is there any other stuff found to share in the gold barn?
Yes it is, I got a few other things, being the 5100 by far the most interesting, but I need some time to process that because now I have a problem of lack of space at home...

User avatar
inmbolmie

21 Jan 2020, 17:24

Bass wrote:
20 Jan 2020, 00:18
That 5100 of yours looks to be in pretty good shape considering it's a barn house find. I suggest wearing gloves when you begin your restoration as the foam underneath the card cage will most likely have turned into a nasty puddle of tar that can be very difficult to wash off.

Good luck on the restoration. A few others here (snuci and I) have also found and restored some 5100's but were unable to get them working. The ROS cards are especially prone to failure, so it would indeed be very impressive if you can get yours to work!
As you said it seems there is something wrong and it points to the ROS board. I've checked the AC circuits, power supply, display connections, buses, etc, everything is OK but doesn't boot. In this site the author explains that booting the machine halted with the SHOW REGISTERS mode enabled you should see in the screen the contents of the first 512 bytes of executable ROS like this:

IMG_2541.JPG
IMG_2541.JPG (230.33 KiB) Viewed 2150 times

But in my case I can see only this:

IMG_6916.JPG
IMG_6916.JPG (220.5 KiB) Viewed 2150 times

I'll investigate a bit deeper into the issue. That keyboard deserves a second opportunity.

User avatar
inmbolmie

24 Jan 2020, 22:26

Bass wrote:
20 Jan 2020, 00:18
That 5100 of yours looks to be in pretty good shape considering it's a barn house find. I suggest wearing gloves when you begin your restoration as the foam underneath the card cage will most likely have turned into a nasty puddle of tar that can be very difficult to wash off.

Good luck on the restoration. A few others here (snuci and I) have also found and restored some 5100's but were unable to get them working. The ROS cards are especially prone to failure, so it would indeed be very impressive if you can get yours to work!
Well, after all it wasn't the ROS the bad component causing the issues. The screen capture with supposedly ROS data that I post wasn't really the right one, the correct is this:

Spoiler:
ros_bad.png
ros_bad.png (956.08 KiB) Viewed 2004 times
Trying to find a logic behind this to give me a clue of the problem I realized that what I was watching was the last column of the first module of correct ROS data repeated over every prior column. So that suggested a problem with the addressing of ROS data. I revised the schematics and tested some signals over the board and isolated the problem over the data address bus in the display controller card.

Then finally detected the real problem: Someone tinkering inside the computer prior to me left this blue jumper cable broken:

Spoiler:
jumper.png
jumper.png (1.95 MiB) Viewed 2004 times
This should be connecting to ground one pin of the address generator circuit but the cable was broken inside and making no contact. I didn't detect this with the prior visual inspection because the cable was in place with no evident signs of being broken, and with so many cables lying around. After fixing this...

Spoiler:
ros.png
ros.png (876.24 KiB) Viewed 2004 times
Now I had the correct ROS data over the screen, so the ROS was OK. Then after activating the RUN switch...

Spoiler:
kb_error.png
kb_error.png (681.6 KiB) Viewed 2004 times
Finally got some text! Apparently the self-checking routine detected a keyboard error, stuck keys. Touched some of the randomly to try to unstuck them, and after another reset...

Spoiler:
basic.png
basic.png (697.15 KiB) Viewed 2004 times

The BASIC prompt, so... It works! But the keyboard doesn't. So now It's time for some keyboard action :mrgreen: .

User avatar
ZedTheMan

24 Jan 2020, 22:39

Oh man, it's like the entirety of the thread before this was just foreplay, haha.

User avatar
Bass

24 Jan 2020, 23:16

Congrats man! I could be wrong but I don't think you'll have much trouble diagnosing your keyboard problem unless there is physical damage somewhere. It's quite easy to remove from the rest of the machine and can then be disassembled just like any other beamspring.

User avatar
inmbolmie

27 Jan 2020, 20:35

Let's get to it. First some images in its original unrestored state.

Spoiler:

rest_01.jpg
rest_01.jpg (619.56 KiB) Viewed 1849 times

Closeup of the spacebar stabilizer, the only part clearly rusted.

rest_02.jpg
rest_02.jpg (437.99 KiB) Viewed 1849 times

Keys

rest_03.jpg
rest_03.jpg (472.98 KiB) Viewed 1849 times
rest_04.jpg
rest_04.jpg (394.46 KiB) Viewed 1849 times
rest_05.jpg
rest_05.jpg (341.09 KiB) Viewed 1849 times

One weird thing is that the back plate is made of plastic instead of metal. It's like after committing to a zinc-cast chassis for the computer they suddenly developed some kind of weight-consciousness when finally adding the keyboard.

Spoiler:
rest_06.jpg
rest_06.jpg (339.87 KiB) Viewed 1849 times

Keycaps off!

Spoiler:
rest_07.jpg
rest_07.jpg (808.48 KiB) Viewed 1849 times
rest_08.jpg
rest_08.jpg (348.73 KiB) Viewed 1849 times

Derusting bath for the spacebar stabilicer.

Spoiler:
rest_09.jpg
rest_09.jpg (220.5 KiB) Viewed 1849 times

Now we go for the creepy part, there is a ton of grime inside this thing. It's unbeliebable how good this keyboard feels giving the amount of crap that it has inside.

Spoiler:
rest_10.jpg
rest_10.jpg (540.63 KiB) Viewed 1849 times

Closeup over THAT FOAM.

Spoiler:
rest_11.jpg
rest_11.jpg (797.01 KiB) Viewed 1849 times
rest_12.jpg
rest_12.jpg (577.82 KiB) Viewed 1849 times
rest_13.jpg
rest_13.jpg (495.2 KiB) Viewed 1849 times
rest_14.jpg
rest_14.jpg (563.35 KiB) Viewed 1849 times
rest_15.jpg
rest_15.jpg (616.2 KiB) Viewed 1849 times


Holy crap!!!! What's THAT THING inside the keyboard :shock: . It looks to me like some kind of alien microscopic civilization from planet Krypton. This is when I started worrying and got some gloves and masks for the rest of the restoration.

After annihilating the poor things, the worst part came, removing that yellow residue took an entire can of glue remover and 3 hours of scrubbing.

Spoiler:
rest_16.jpg
rest_16.jpg (936.13 KiB) Viewed 1849 times

Now the switches, there was only 3 casualties, one bent stem, one dislodged flyplate and one broken slider arm. All easily fixed. The broken slider was fixed with some superglue.

Spoiler:
rest_17.jpg
rest_17.jpg (437.96 KiB) Viewed 1849 times
rest_18.jpg
rest_18.jpg (564.67 KiB) Viewed 1849 times
rest_19.jpg
rest_19.jpg (479.81 KiB) Viewed 1849 times

Final result for the cleaned parts.

Spoiler:
rest_20.jpg
rest_20.jpg (697.61 KiB) Viewed 1849 times
rest_21.jpg
rest_21.jpg (691.2 KiB) Viewed 1849 times
rest_22.jpg
rest_22.jpg (648.8 KiB) Viewed 1849 times
rest_23.jpg
rest_23.jpg (621.85 KiB) Viewed 1849 times

Two of the switches were black instead of grey, so it seems they were replacement parts but were otherwise indistinguishable.

rest_24.jpg
rest_24.jpg (551.21 KiB) Viewed 1849 times


Cutting some new foam.

Spoiler:
rest_25.jpg
rest_25.jpg (713.28 KiB) Viewed 1849 times

One thing I wasn't aware of, it seems that this particular beam spring has a symmetrical stem. Here compared with a regular sloped stem.

Spoiler:
rest_26.jpg
rest_26.jpg (383.29 KiB) Viewed 1849 times

The aluminium top plate is pretty light, weighting only 220 grams.

Spoiler:
rest_27.jpg
rest_27.jpg (292.71 KiB) Viewed 1849 times

The keyboard with switches in place. I applied some PTFE dry lube to the sliders for extra smoothness.

Spoiler:
rest_28.jpg
rest_28.jpg (585.17 KiB) Viewed 1849 times

The whole assembly without caps weights only 1,32 Kg. Or approx. two and a half apple aluminum keyboards in Standard Chyros Units (SCU).

Spoiler:
rest_29.jpg
rest_29.jpg (363.14 KiB) Viewed 1849 times

Testing it before putting keycaps in, everything working now.

Spoiler:
rest_30.jpg
rest_30.jpg (455.84 KiB) Viewed 1849 times

Posing next to a distant relative.

Spoiler:
rest_31.jpg
rest_31.jpg (385.97 KiB) Viewed 1849 times

The space where the keyboard goes inside the case.

Spoiler:
rest_32.jpg
rest_32.jpg (344.45 KiB) Viewed 1849 times

Keyboard installed and working.

rest_33.jpg
rest_33.jpg (321.68 KiB) Viewed 1849 times

Next step will be creating reproductions for the missing keycaps. This is going to take some time because It's a first for me.

And also try to make the tape unit work. When I started with this project I thought that I would have for sure to replace the DC motor rubber band... But why using a DC motor and rubber band when you can use an AC motor and a frikkin' transmision belt?

Spoiler:
rest_34.jpg
rest_34.jpg (401.87 KiB) Viewed 1849 times

This thing is definitively built like a truck.

User avatar
SneakyRobb
THINK

27 Jan 2020, 21:42

Aluminium barrel plate, plastic backplate. Very interesting. That foam does look like some kind of moss collection as well. That plate is actually quite aesthetic tbh. Well done.
inmbolmie wrote:
27 Jan 2020, 20:35

The keyboard with switches in place. I applied some PTFE dry lube to the sliders for extra smoothness.

The whole assembly without caps weights only 1,32 Kg. Or approx. two and a half apple aluminum keyboards in Standard Chyros Units (SCU).
Absolute madman lubricating beamsprings!

That weight is Actually shocking.

User avatar
AJM

27 Jan 2020, 22:07

Fascinating! Thanks for the documentation.

manisteinn

27 Jan 2020, 23:27

Great find and nice detailed pictures!

I've modeled, printed and resin cast beamspring caps so I could potentially help you out with that, here are some thoughts:

I assume both your shift keys have identical stem placements, is that right?
I'd happily cast a copy for you for the cost of materials, but I only have the 3278 and Selectric sets so you'd have to send it. There's of course the risk of it getting lost in transit, I'm not sure I'd do it myself. Perhaps you could find someone local to do a 1:1 copy.
I could use my non-stepped 1.25 and 1.5u shift keys, but those would leave a gap and wouldn't be a great match.
A selectric 2u shift is probably the closest, the edges could be filed to 1.75u.

Is the CMD key unique to this series? I'd think a flipped 5251/displaywriter return key would be the closest fit but I don't have any of those either. If anyone does and is ok with sending it I'd happily cast a copy of it.

I recently made resin copies of SLA prints which turned out great, that's also an option for prints based on 3d scanned or modeled originals.
I don't have any real experience with the durability and longevity of more expensive SLA/SLS prints but my cheap ones yellowed significantly within a year, resin casting also allows for closer color matching.

Hope this helps

User avatar
inmbolmie

28 Jan 2020, 21:05

manisteinn wrote:
27 Jan 2020, 23:27

I'd happily cast a copy for you for the cost of materials, but I only have the 3278 and Selectric sets so you'd have to send it [...]
Thanks for your support, I have been for some time thinking about trying to cast some keycaps and this is one good opportunity so I think I will try first myself. I'm reading now some posts here and there looking for "inspiration".
manisteinn wrote:
27 Jan 2020, 23:27

I assume both your shift keys have identical stem placements, is that right? [...]

Is the CMD key unique to this series? I'd think a flipped 5251/displaywriter return key would be the closest fit but I don't have any of those either. [...]
With regard to the shift key...

Foto 28-1-20 20 34 34.jpg
Foto 28-1-20 20 34 34.jpg (770.15 KiB) Viewed 1699 times

Luckily it has a double-mount so It can work as left or right shift indistinctively.


And about the 5251 Return...

Foto 28-1-20 20 36 29.jpg
Foto 28-1-20 20 36 29.jpg (1.03 MiB) Viewed 1699 times

It fits, but I think it has the wrong slopes, changed between upper and lower part. But it just works and will be good enough to use it as a mold.

manisteinn wrote:
27 Jan 2020, 23:27


I've modeled, printed and resin cast beamspring caps


Very nice keycaps by the way, with these I only aspire to "fill the gap" because I know no matter how hard I try the new keycaps won't ever look original.

manisteinn

28 Jan 2020, 22:27

inmbolmie wrote:
28 Jan 2020, 21:05

Thanks for your support, I have been for some time thinking about trying to cast some keycaps and this is one good opportunity so I think I will try first myself. I'm reading now some posts here and there looking for "inspiration".
Nice, it's quite fun :)

Feel free to ask if you want any tips. I'll mention that the stem shape being so deep and narrow makes the bottom mold fragile, there's quite some pulling force required when demolding and a loud pop when the vacuum finally breaks. Both of mine got progressively looser and eventually ripped (last picture)
It's not a big deal if you're just doing a couple of caps though, and you can of course reinsert the original keycap in the intact top mold and just repour the bottom.

For future molds I'm planning to try out metal stem inserts for improved consistency and longevity.
inmbolmie wrote:
28 Jan 2020, 21:05


With regard to the shift key...

Foto 28-1-20 20 34 34.jpg

Luckily it has a double-mount so It can work as left or right shift indistinctively.
Interesting, the selectric 2u key also has a similar stem pattern
inmbolmie wrote:
28 Jan 2020, 21:05
And about the 5251 Return...

Foto 28-1-20 20 36 29.jpg

It fits, but I think it has the wrong slopes, changed between upper and lower part. But it just works and will be good enough to use it as a mold.
Great! You already have one :)

I figured it'd be the wrong profile, you should be able to get much closer to the original by filing the bottom surface to the correct angle.

User avatar
inmbolmie

02 Mar 2020, 15:03

One final update to this thread, covering the making of reproduction keycaps and the tape drive operation.

Planning for the keycap reproductions I reviewed carefully some topic specific threads like those from manisteinn and others for “inspiration”. I bought locally some molding and casting materials, and it wasn’t cheap at all, as you have to buy all materials in quantities that far exceed what you really need for a couple of castings (silicone, curing agent, two-component polyurethane resin, clay, vaseline and pigments).

Some images of the keycap casting process.

Spoiler:


I made 2 part silicone molds. The container is built with some “borrowed” lego pieces. For the keytop mold the bottom part is sealed with modelling clay, and for the second mold the silicone is covered with a layer of vaseline so that you can later separate them easily.

The tricky part is creating some “channels” for the polyurethane to be injected when the mold is closed (and for the air bubbles to escape). I made them using some chopsticks hot glued to the keycaps in key areas.

mold1.jpg
mold1.jpg (274.22 KiB) Viewed 1289 times

The finished molds. This part is very time consuming as the silicone takes 24 hours to cure for each side of the mold.

mold2.jpg
mold2.jpg (196.81 KiB) Viewed 1289 times
mold3.jpg
mold3.jpg (324.12 KiB) Viewed 1289 times
mold4.jpg
mold4.jpg (229.53 KiB) Viewed 1289 times

One of the molds after the polyurethane injection. The red glowing thing next to the mold is a massaging device taped to the table, with the idea of adding some vibration to help the air bubbles escape.

mold5.jpg
mold5.jpg (285.39 KiB) Viewed 1289 times

Demolded keys. There were some bubbles at the bottom but this was expected. For perfect results I suppose you will need the vacuum chamber/pressure pot combo, but that would be horribly expensive for just a couple of keycaps.

keys1.jpg
keys1.jpg (232.8 KiB) Viewed 1289 times
keys2.jpg
keys2.jpg (239.67 KiB) Viewed 1289 times

I used black and white pigments to try to replicate the original colors, the matching is not perfect but good enough.

The result was better than expected, there is only one small bubble in the visible part of the shift key and it is hardly noticeable in real operation. The key feel and stem fit is exactly the same as the original keys.

Mounted keys:

keys3.jpg
keys3.jpg (290.21 KiB) Viewed 1289 times

Final result, as I said better than expected and much much better than having an empty space there.

keys4.jpg
keys4.jpg (291.68 KiB) Viewed 1289 times

Finally some images of the tape drive, and the discovery of the original purpose of this machine

Spoiler:


The drive needed only some light cleaning. The cooling fan motor and cover needed also some derusting.

tape1.jpg
tape1.jpg (307.17 KiB) Viewed 1289 times
tape2.jpg
tape2.jpg (244.27 KiB) Viewed 1289 times
tape3.jpg
tape3.jpg (426.13 KiB) Viewed 1289 times
tape4.jpg
tape4.jpg (339.45 KiB) Viewed 1289 times
tape5.jpg
tape5.jpg (397.3 KiB) Viewed 1289 times
tape6.jpg
tape6.jpg (379.29 KiB) Viewed 1289 times
tape7.jpg
tape7.jpg (298.94 KiB) Viewed 1289 times

One part still incomplete is that there should be four little wheels mounted over beam springs that hold the tape once inserted against the drive wheel and magnetic head. Unfortunately it seems that the material those wheels are made of isn’t durable, and three of them are broken and missing. Because of this, for the tape to operate you have to hold it firmly in place with your hand. It seems that is a common problem as I’ve seen youtube videos that show the tape operation where the operator has to hold the tape in place like I have to.

In this image you can see the surviving wheel and the place where one of the missing wheels should be.

tape8.jpg
tape8.jpg (292.16 KiB) Viewed 1289 times

Now I wanted to try to recover some programs from the tape that came with the machine.

The tape had its tensioning band totally disintegrated, so I ordered some “plastibands”, like those used in this video from CuriousMarc to restore some similar tapes (they had to be imported from Amerika , though!) https://www.youtube.com/watch?v=wuMBOiwPnOg

tape9.jpg
tape9.jpg (371.67 KiB) Viewed 1289 times
tape10.jpg
tape10.jpg (343.76 KiB) Viewed 1289 times

The tape surface is in very bad shape but anyway I was able to load the BASIC program it has stored. It turned out that this machine was used for making and printing lists of structural steel construction materials (beams, plates and stuff like that). I suppose that the printed lists were later loaded into the factory main computer (a system/36, system/38 or something similar) using a nice 5251 terminal for procurement, fabrication, invoicing, etc.

program.jpg
program.jpg (288.85 KiB) Viewed 1289 times

And that’s all for this IBM 5100, I still have to finish the tape drive restoration and try to make the printer work, but that won’t be so relevant for keyboard enthusiasts.

Thanks for tuning in!

User avatar
Raumfahrer

02 Mar 2020, 15:19

what an amazing thread, and a great job at bringing this thing back to life!

andrewjoy

02 Mar 2020, 15:22

inmbolmie wrote:
02 Mar 2020, 15:03

And that’s all for this IBM 5100, I still have to finish the tape drive restoration and try to make the printer work, but that won’t be so relevant for keyboard enthusiasts.
Hey! We want to see it all !

Fantastic work getting this thing back up and running. Clearly a labour of love.

Show photos and videos ones its 100% !

Post Reply

Return to “Gallery”