Osborne1-KeyboardReplacement

Osborne1-KeyboardReplacement

Replacement keyboard using Cherry MX switches, for if your Osborne 1 keyboard had a bad membrane like mine.

I think there are some Osborne 1 keyboards that are a different layout, which this may not work with.

If your Osborne 1 is like mine, I need an ISO '3' number-row key with £ sign instead of #. I think this comes down to the ROM in your system.

This is a slightly advanced project to mount to the original enclosure. You must:

• Shorten the original 8-32 hex spacers to about half, or buy the replacements in the BoM.
• Shorten the original 8-32 bolts to about 4.5mm thread length, or buy replacements.
• Figure out how to stop the PCB flexing in the middle. Two holes on the PCB are provided to add additional spacers and bolts for the easiest method (drill 2 holes in the original metal faceplate for this). If you wish to not deface the original plate, you will need to fashion something to sit behind the keyboard PCB in the enclosure.

BoM:

• PCB
• 69 x Cherry-MX-compatible keycaps
• 68 x Cherry MX-compatible PCB-mount switches (Cherry MX1A-11NW)
• 1 x Cherry MX Lock switch (Cherry MX1A-31NW)
• 1 x Cherry MX stabiliser kit for 2u-2.75u (Cherry G99-0742)
• 1 x Cherry MX stabiliser kit for 8u-10u (Cherry G99-0744)
• 1 x 2x10-pin 2.54mm vertical locking IDC connector (TE 5499206-4)
• 4 x 3/8" long 8-32 hex spacer (RAF 2102-832-AL)
• 4 x 3/16" threaded-length 8-32 bolts
• 2 x 3/8" long hex spacers (I used M3 threaded) (only used for my method of mounting, involving drilling 2 holes in the front plate)

Notes:

• I recommend Cherry MX Black, as it's closest to the original feel (it feels better imo).
• Cherry MX Lock are obsolete and hard to find. You can replace with another latching switch in a bodgy manner if you can't find one. I found a panel-mount one, and used epoxy for strength since it didn't have the PCB-mounting nubs.
• 9 of the keycaps need to be custom-made, the rest are from standard ANSI and ISO sets. I used the DSA Dolch set from Signature Plastics as my base.

Standard keycaps:

• Letters (26 keys)
• Esc and arrow keys (5 keys)
• Tab (1.5u)
• Numpad 1-9 and . (10 keys)
• Number row, from 1 to = (12 keys) (ANSI or ISO '3' key depending on your ROM)
• Punctuation ( < > ? : " ) (5 keys)
• Backslash/pipe key (1u) (from ISO set)
• Spacebar (8u) (I used their DSA-profile black one)

Custom keycaps:

• Square bracket key (1u)
• Return (2u)
• 2 x Shift (1.5u)
• Alpha Lock (1u)
• Enter (1u)
• Numpad 0 (1u)
• Ctrl (1u)