Bringing An IBM Butterfly Laptop Back From The Dead

Among all the laptops produced over the last few decades, there is one which rises above the rest and which has retained an appeal long after its meager computing resources became obsolete. It’s the IBM 701c, the famous “Butterfly” laptop, whose fold-out keyboard still gives it star  quality, and [John Graham-Cumming] has documented the restoration of one from the tattered remains of two scrap examples.

The two laptops in question were someone else’s never-started project, and were in a sorry state. The flexible cables were in poor condition, and the 1990s Ni-MH batteries had leaked and damaged both circuits and case. We were unaware that NiMH leakage could damage plastic, but the parts of these machines were significantly damaged.

One had a working mainboard, the other a working modem card. One keyboard was in pretty bad shape, the other was complete. Of the pair there was a double super twisted nematic (DSTN) display and a more contemporary thin film transistor (TFT) panel. Be thankful if you have never had to use a DSTN laptop, as they were truly awful. From this pile of parts a working machine could be made, and with a new CMOS battery, that cable repair, and a repaint, he was ready. Or at least, as he says, ready for 1995.

This isn’t the first 701c restoration we’ve seen, and within reason, it’s even possible to give them a retro processor upgrade.

Restoration Of A Thinkpad 701C

This is like ASMR for Hackers: restoration specialist [Polymatt] has put together a video of his work restoring a 1995 IBM Thinkpad 701c, the famous butterfly keyboard laptop. It’s an incredible bit of restoration, with a complete teardown and rebuild, even including remaking the decals and rubber feet.

[Polymatt] runs Project Butterfly, an excellent site for those who love these iconic laptops, offering advice and spare parts for restoring them. In this video, he does a complete teardown, taking the restored laptop completely apart, cleaning it out, and replacing parts that are beyond salvaging, like the battery, and replacing them. Finally, he puts the whole thing back together again and watches it boot up. It’s a great video that we’ve put below the break and is well worth watching if you wonder about how much work this sort of thing involves: the entire process took him over two years.

We’ve covered some of his work in the past, including the surprisingly complicated business of analyzing and replacing the Ni-Cad battery that the original laptop used. Continue reading “Restoration Of A Thinkpad 701C”

The ThinkPad You All Wish You Had, With A Brain That’s Not Ancient

An IBM (or, later, Lenovo) ThinkPad is a popular choice in our community. They’re prized for their rugged design, longevity, and good software support. Over the many years that the line has been available, there have been a few models which have captured the attention more than others, and among those, probably the most sought-after is the ThinkPad 701c. It would be an unremarkable mid-1990s 486 laptop were it not for the party piece of that flip-out butterfly keyboard (see video, below). [Karl Buchka] has one that’s profoundly dead, and rather than use it as a novelty paperweight, he’s giving it a new lease of life with a Framework motherboard.

This is very much a work in progress, so there will be plenty more to come, but so far, he’s taken the display panel from an iPad and made it work with the Framework board, and designed an entirely new lower case for the Thinkpad. This will hold the Framework board with its USB-C ports at the edge, so in the place of its USB-based expansion modules, he’s made a custom external port replicator. Meanwhile, a Teensy handles that unique keyboard. We’re told that the design files will all eventually be put online should anyone else want to try.

We’d normally be slightly upset were someone to butcher something as unusual as a 701c, however, in thic ase we can see that it turns a broken computer into one that should see quite a bit of use.  We can’t help envying him this project.

Understandably not many 701c owners have dived inside their machines, but we have previously brought you a contemporary processor upgrade. If you’ve never seen the 701c’s keyboard — or you just want to see it again — here you go:

Thanks [Ł. Juszczak] for the tip.

Thinkpad 701c: Reverse Engineering A Retro Processor Upgrade

[Noq2] has given his butterfly new wings with a CPU upgrade. Few laptops are as iconic as the IBM Thinkpad 701 series and its “butterfly” TrackWrite keyboard. So iconic in fact, that a 701c is part of the permanent collection of the Museum of Modern Art in New York.

Being a 1995 vintage laptop, [Noq2’s] 701c understandably was no speed demon by today’s standards. The fastest factory configuration was an Intel 486-DX4 running at 75 MHz. However, there have long been rumors and online auctions referring to a custom model modified to run an AMD AM-5×86 at 133 MHz. The mods were performed by shops like Hantz + Partner in Germany. With this in mind, [Noq2] set about reverse engineering the modification, and equipping his 701c with a new processor.

thinkpad-brainsurgeryThe first step was determining which AMD processor variant to use. It turns out that only a few models of AMD’s chips were pin compatible with the 208 pin Small Quad Flat Pack (SQFP) footprint on the 701c’s motherboard. [Noq2] was able to get one from an old Evergreen 486 upgrade module on everyone’s favorite auction site. He carefully de-soldered the AM-5×86 from the module, and the Intel DX4 from the 701c. A bit of soldering later, and the brain transplant was complete.

Some detailed datasheet research helped [noq2] find the how to increase the bus clock on his 5×86 chip, and enable the write-back cache. All he had to do was move a couple of passive components and short a couple pins on the processor.

The final result is a tricked out IBM 701c Thinkpad running an AMD 5×86 at 133 MHz. Still way too slow for today’s software – but absolutely the coolest retro mod we’ve seen in a long time.