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ThinkPad 701C Framework Transplant

The ThinkPad 701C Framework Transplant is a project by Karl Buchka (Karl_Buchka) that installs a Framework Laptop 13 mainboard into the chassis of an IBM ThinkPad 701C "Butterfly" — a compact subnotebook from 1995 famous for its expanding butterfly keyboard1. First posted in February 2023, the project features a fully functional original keyboard and TrackPoint, an iPad 7 display panel, and a custom integration board — all fitting within the original 701C's 10-inch footprint1. Framework CEO Nirav Patel gave the project a shoutout during a live Q&A in June 20231.

The ThinkPad 701C​

The IBM ThinkPad 701C (codenamed "Butterfly") was sold briefly in 1995 as a compact subnotebook with a ~10" footprint1. Its signature feature is a full-sized keyboard that expands outward in a butterfly motion as the lid is opened, using a four-bar linkage mechanism1. The 701C is highly sought after by collectors, with intact units selling for hundreds of dollars1. The laptops are notorious for brittle plastic that cracks with age1.

Design​

Display​

Buchka discovered that the iPad 7 panel (10.2", 2160×1620) is an almost perfect dimensional match to the original 701C screen12. The panel connects to the Framework mainboard's internal eDP connector via a custom adapter. The display required reverse-engineering the panel's connector pinouts and designing a boost converter for the backlight2. On the software side, the panel "just works" since both the iPad and original Framework panels use standardized four-lane DisplayPort interfaces1.

Keyboard and TrackPoint​

The original 701C keyboard and TrackPoint are connected to a Teensy 3.6 microcontroller running a customized build of QMK firmware, which enumerates both as standard USB input devices1. The keyboard's row/column lines connect directly to the Teensy. The TrackPoint strain elements run through a Sprintek 8707 TrackPoint-to-PS/2 board, then to the Teensy1.

The original keyboard connectors are Molex 52204 series (0.625 mm pitch), which are discontinued. Buchka sourced new-old-stock from Quest Components and designed custom breakout boards1.

Integration Board​

The centerpiece of the electronics is a custom "integration board" that handles1:

  • Keyboard and TrackPoint input (via Teensy 3.6 + QMK)
  • Wi-Fi/Bluetooth (relocated M.2 module via a "U-turn" FFC ribbon)
  • Lid closure sensor
  • Indicator LEDs (Caps Lock, Num Lock, Scroll Lock)
  • Power button
  • Audio board passthrough

Since the Framework mainboard sits flush against the right side of the 701C case, the Wi-Fi/BT M.2 module couldn't be installed directly. Buchka designed a 7.5 mm wide "U-turn" board with an M.2 card-edge interface that flips all conductors 180° onto a high-density FFC cable, routing them to the integration board1. Despite being "highly abusive of the USB and PCIe routing standards" (2-layer, no impedance matching), it tested at ~1 GB/s — matching commercial USB-C cables1.

USB Hub​

A custom 4-port USB hub board connects to one of the left USB-C ports on the Framework mainboard, exposing1:

  • 2× USB-A (external)
  • 1× USB-A (internal, for Logitech dongle)
  • 1× Gigabit Ethernet

Ports and I/O​

PortSource
2× USB-CDirect from Framework mainboard (right side)
2× USB-ACustom USB hub (left side)
1× Gigabit EthernetCustom USB hub (left side)
Headphone jackFramework audio board
Wi-Fi / BluetoothRelocated M.2 module via U-turn board
Power buttonCustom PCB with tactile switch

No Framework expansion cards are used — the ports are exposed directly1.

Case​

Buchka designed an entirely new lower case and hinge bracket, since the original 701C internals are fundamentally incompatible with the Framework mainboard1. The case is designed in Fusion 360 with 1 mm thick side walls1. Final production used glass-filled Nylon-12 MJF printing from Xometry (~$200 USD for the bottom case)1.

A replacement top cover was also designed, since the original was in five pieces. The new top cover is compatible with unmodified 701Cs and could be useful for restoration of original machines1.

Technical Specifications​

SpecificationDetails
ChassisIBM ThinkPad 701C ("Butterfly", 1995)
ComputeFramework Laptop 13 mainboard (11th Gen Intel)
DisplayiPad 7 panel, 10.2" 2160×1620, via eDP2
KeyboardOriginal 701C butterfly keyboard, via QMK/Teensy 3.61
TrackPointOriginal 701C TrackPoint II, via Sprintek 8707 + Teensy1
BatteryFramework Laptop 13 stock battery1
CaseCustom 3D-printed (MJF glass-filled PA12)1
PCB DesignAltium Designer1
CADFusion 3601
Sourcebasketofkittens/framework701c (GitHub)3

Development Timeline​

DateMilestone
Feb 2023Project announced with first mock-up1
Feb 2023Covered by Tom's Hardware, PCWorld, The Register4
Jun 2023Nirav Patel shoutout on Framework live Q&A1
Jun 2023Keyboard and TrackPoint fully functional1
Jun 2023Integration board assembled, power-on testing successful1
Jan 2024PCB designs published on GitHub3
Feb 2024USB hub design finalized1
Feb 2024MJF case ordered from Xometry ($200+)1
Mar 2025Community member Sour begins building own 701C transplant1
Jul 2025Community member Brian_Zhou begins build, asks about battery tab fitment1

Community Extensions​

The project inspired several community efforts1:

  • TheForgottenKing — Built a similar 701C transplant using a LattePanda Alpha, transplanting a TrackPoint IV module (which speaks PS/2) instead of the original TrackPoint II, and a 9.7" iPad LCD via USB-C DP Alt Mode1
  • GGigabiteM — Began a 701CS transplant from a battery-leaked donor unit, with Buchka providing Molex 52204 connector breakout boards1
  • Barkeep — Modeled replacement 701C case parts and published them on Printables/MakerWorld; planned to reverse-engineer and model the butterfly keyboard mechanism in SolidWorks1
  • polymatt — Created and published full 3D-printable 701C replacement case parts on Printables1
  • Sour — Built a Framework 701C with a JIS keyboard, remapped the key matrix pin-by-pin for QMK1

Media Coverage​

  • Tom's Hardware — "IBM Thinkpad 701C Receives 21st Century 'Brain Transplant'"4
  • PCWorld — "Legendary IBM 'butterfly' ThinkPad resurrected with Framework guts"4
  • The Register — "Bringing the IBM Thinkpad 'Butterfly' back to life"4
  • r/thinkpad — Front page of the ThinkPad subreddit1

Footnotes​

  1. Thinkpad 701C with a Framework brain transplant (work in progress) — Framework Community (Karl_Buchka, February 2023 – July 2025) ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9 ↩10 ↩11 ↩12 ↩13 ↩14 ↩15 ↩16 ↩17 ↩18 ↩19 ↩20 ↩21 ↩22 ↩23 ↩24 ↩25 ↩26 ↩27 ↩28 ↩29 ↩30 ↩31 ↩32 ↩33 ↩34 ↩35 ↩36 ↩37 ↩38 ↩39 ↩40 ↩41 ↩42

  2. 10.2" iPad 7 display on the internal eDP connector — Framework Community (Karl_Buchka, February 2023) ↩ ↩2 ↩3 ↩4

  3. basketofkittens/framework701c — GitHub ↩ ↩2

  4. IBM Thinkpad 701C Receives 21st Century 'Brain Transplant' — Tom's Hardware (February 2023) ↩ ↩2 ↩3 ↩4