2 layers225.2 × 48.2 mm
Mx unsaver frow
nearestexit/mx-unsaver
Custom Keyboard & Numpad inspired by the IBM "Unsaver", designed with Onshape and KiCad
57 parts40MIT
2 layers391.8 × 105.4 mm
Mx unsaver main
nearestexit/mx-unsaver40Custom Keyboard & Numpad inspired by the IBM "Unsaver", designed with Onshape and KiCad
- Size
- 391.8 × 105.4 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 248
- Nets
- 145
- Pads
- 826
- Tracks, vias
- 1,684, 321
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 19 Jan 2026
- Updated
- 30 Aug 2026
Overview
Mx unsaver main is an open-source printed circuit board by nearestexit, from the nearestexit/mx-unsaver repository on GitHub, published under the MIT licence. It is a 2-layer board of 391.8 × 105.4 mm with 248 parts on 145 nets, routed with 1,684 tracks and 321 vias.
Its parts include 98 diodes, 9 capacitors, 9 resistors, 7 switches and 6 connectors. It belongs with the keyboards and input boards and the STM32 boards of this library.
README
README.mdmx-unsaver
Custom keyboard and numpad inspired by vintage Cherry keyboards and the IBM "Unsaver". Designed in Onshape and KiCad. Powered by QMK.
Overview
- Side profile and shape inspired by the Cherry G80-5700 and G80-1800
- PCB Top-Mount
- Integrated USB Hub with 1x USB-C Upstream port and 2x USB-C and 2x USB-A Downstream ports
- Brass through-weight
Case Source (Onshape): https://cad.onshape.com/documents/1d9e79a61d42e7395c429f47/w/28912f958105e1c831f67a9e/e/537bd51b2d234361e6d6eea3
PCB
The PCB supports ISO and ANSI. Unfortunately, due to an oversight, the Case only supports ANSI enter. It could be relatively easily modified to support ISO enter. I ordered single bare PCBs from EuroCircuits and OSHPark and hand-soldered the components, so I do not have JLCPCB production files available.
Important: The PCB has the words "Made In Germany" printed on it. This is because it was actually manufactured in Germany. If you choose to have it manufactured in China, please remove this logo from the PCB.
Bill of Materials
| Item | Quantity | Link |
|---|---|---|
| M2x4x3mm Hex Standoff | 2 | https://www.ebay.com/itm/355663469861?var=624766479032 |
| M2x3x4mm Wafer head Screw | 2 | https://www.ebay.com/itm/355676691340?var=624776776427 |
| Feet | 8 | https://cannonkeys.com/products/akb-feet |
| M2.5x8mm BHCS | 57 | https://mcmaster.com/92095A459 |
| M2.5x6mm SHCS | 14 | https://mcmaster.com/91292A010 |
| M2.5x10mm SHCS | 7 | https://mcmaster.com/91292A014 |
| M2.5x25mm SHCS | 6 | https://mcmaster.com/91292A036 |
| M2.5x20mm SHCS | 4 | https://mcmaster.com/91292A019 |
| M3x6mm Countersunk | 5 | https://mcmaster.com/92125A126 |
| M3x8mm Countersunk | 9 | https://mcmaster.com/92125A128 |
| 1:1 JST-SH Cable (50mm) | 3 | https://www.digikey.com/en/products/detail/adafruit-industries-llc/4210/10230021 |
| FPC Cable (50.8mm) | 1 | https://www.digikey.com/en/products/detail/molex/0151660207/3281088 |
USB Hub
The USB Hub utilizes two FE1.1S USB 2.0 HS Hub chips in series. It can deliver a total of 400mA downstream (the keyboard is assumed to use 100mA).
Firmware
A QMK .bin file is provided for flashing, as well as QMK source files.
(The original Unsaver in this picture is not for sale.)
Parts
248| Qty | Value | Footprint | References |
|---|---|---|---|
| 89 | D_Small | mx-unsaver:D_SOD-123_ShiftedSilkscreen | D1, D10, D11, D12, D102, D103, D104, D105, D106, D107, D108, D109, D110, D112, D120, D121 +73 |
| 78 | MX_SW_solder | mx-unsaver:SW_MX_1u_PCBMount | MX1, MX10, MX11, MX12, MX106, MX107, MX108, MX109, MX111, MX112, MX113, MX114, MX115, MX116, MX117, MX118 +62 |
| 12 | MountingHole | MountingHole:MountingHole_2.7mm_M2.5 | H1, H2, H3, H4, H5, H6, H7, H8, H9, H10, H11, H12 |
| 8 | 1k | Resistor_SMD:R_0805_2012Metric | R2, R3, R4, R6, R8, R17, R18, R19 |
| 7 | MX_SW_solder | mx-unsaver:SW_MX_1u_PCBMount_NoLeft | MX17, MX92, MX93, MX95, MX119, MX122, MX126 |
| 6 | MX_SW_solder | mx-unsaver:SW_MX_1u_PCBMount_NoRight | MX15, MX18, MX91, MX97, MX100, MX110 |
| 4 | 100n | Capacitor_SMD:C_0603_1608Metric | C1, C2, C5, C7 |
| 4 | MX_stab | mx-unsaver:STAB_MX_2u_FixedDistance | S2, S3, S4, S5 |
| 3 | 1u | Capacitor_SMD:C_0805_2012Metric | C3, C8, C9 |
| 3 | MX_SW_solder | mx-unsaver:SW_MX_1u_3pin | MX121, MX123, MX127 |
| 2 | 4.7u | Capacitor_SMD:C_0603_1608Metric | C4, C6 |
| 2 | Conn_01x01 | mx-unsaver:PinHeader_1x01_P2.54mm | J4, J5 |
| 2 | Conn_01x02 | mx-unsaver:PinHeader_1x02_P2.54mm_BOOT | J1, J2 |
| 2 | MadeInGermany | mx-unsaver:MadeInGermany | G1, G2 |
| 2 | MountingHole | mx-unsaver:HOLE_BackSpace_Slots | H15, H16 |
| 2 | MountingHole | mx-unsaver:MountingHole_2.2mm_M2_Standoff | H13, H14 |
| 1 | 10k | Resistor_SMD:R_0805_2012Metric | R1 |
| 1 | Conn_01x04_MountingPin | Connector_JST:JST_SH_SM04B-SRSS-TB_1x04-1MP_P1.00mm_Horizontal | J3 |
| 1 | Conn_01x20_MountingPin | mx-unsaver:CONN-SMD_20P-P0.50_10051922-2010ELF | J6 |
| 1 | LED_CAPS1 | mx-unsaver:LED_MX_3mm_Offset | D86 |
| 1 | LED_CAPS2 | mx-unsaver:LED_MX_3mm_Offset_Flipped | D78 |
| 1 | LED_LAYER1 | mx-unsaver:LED_MX_3mm_Offset_Flipped | D137 |
| 1 | LED_LAYER2 | mx-unsaver:LED_MX_3mm_Offset_Flipped | D71 |
| 1 | LED_LAYER3 | mx-unsaver:LED_MX_3mm_Offset_Flipped | D72 |
| 1 | LED_LAYER4 | mx-unsaver:LED_MX_3mm_Offset_Flipped | D73 |
| 1 | LED_LAYER5 | mx-unsaver:LED_MX_3mm_Offset_Flipped | D87 |
| 1 | LED_NUM | mx-unsaver:LED_MX_3mm_Offset_Flipped | D135 |
| 1 | LED_SCLK | mx-unsaver:LED_MX_3mm_Offset_Flipped | D136 |
| 1 | MX_SW_solder | mx-unsaver:SW_MX_1u_PCBMount_NoMiddle | MX125 |
| 1 | MX_SW_solder | mx-unsaver:SW_MX_1u_NoHoles | MX124 |
| 1 | MX_stab | mx-unsaver:STAB_MX_2u_FixedDistance_Enter_Modified | S1 |
| 1 | MX_stab | mx-unsaver:STAB_MX_2u_FixedDistance_ISO_Modified | S6 |
| 1 | MX_stab | PCM_marbastlib-mx:STAB_MX_10u | S7 |
| 1 | MountingHole | mx-unsaver:HOLE_LShift_Slots | H17 |
| 1 | MountingHole | mx-unsaver:HOLE_RShift_Slots | H18 |
| 1 | MountingHole | mx-unsaver:HOLE_Enter_Slots | H19 |
| 1 | STM32F072CBTx | Package_QFP:LQFP-48_7x7mm_P0.5mm | U1 |
| 1 | XC6206PxxxMR | Package_TO_SOT_SMD:SOT-23-3 | U2 |
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Questions
How big is the Mx unsaver main PCB?
It measures 391.8 × 105.4 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Mx unsaver main use?
248 parts. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Mx unsaver main KiCad files?
From the nearestexit/mx-unsaver repository on GitHub, at the commit this page was made from: the board is mx-unsaver-main/mx-unsaver-main.kicad_pcb and its schematic Numpad_Daughterboard/Numpad_Daughterboard.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Mx unsaver main design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).