On 7/9/20 9:34 PM, Ian Finder via cctalk wrote:
The correct SD-series replacement switch would be the 4B3A-
It would be interesting to understand the failure mode. I wonder if they passivated the die correctly? 4B3A is a non-multiplexed contact closure type which is extremely difficult to find. The modules out of any xx3A switch should work. The first two are the part number of the switch body. The switch type is stamped into the left side of the switch module plastic so all you need to do is pop off the keytop to read it.
