Original Alps momentary switch for Roland TR-808 Start/Stop or Tap functions. I have a Limited number of these switches available - removed from a spare MC-4 key panel. Alps part number KEH10903 - these switches were used in the MC-4B MicroComposer and I've seen them in later versions of the TR-808. Originally 808s used part number KED10903 which is functionally identical, the difference being that the earlier switches have white stems and are sealed which makes cleaning & repairing them quite tricky. This later style switch is a big improvement and can be taken apart for cleaning should it become necessary in the future. These switches are a drop-in replacement, no problem with fitting the original key caps.
They have seen little use and are in excellent working condition- all have been cleaned and tested for continuity in a working TR-808. It’s almost impossible to find these switches “new” today, so if keeping your gear as original as possible is important to you they may be of interest - but be quick, I don’t know if I will have any more once these are gone.
Alternatively, I have replacement Cherry MX switch assemblies available here.
Only attempt switch replacement if you are confident you have the skills to do so. If in doubt ask a synth tech to do it for you - it’s all too easy to damage the circuit board if you’re inexperienced with soldering/desoldering.
Note: These switches are also compatible with the MC-4 MicroComposer, Boss DR-55 & similar rhythm machines and possibly other Roland equipment of the same period that uses this type of momentary switch. Check your service manual for part number.