SAM4s SPS-300 series replacement keyboard fits in both the SPS-320 and the SPS-340 model cash registers. This part is pretty simple to replace by the end-user. Probably about a twenty minute job give or take a few minutes.
The power cord must be unplugged from power before attempting to remove and replace the keyboard. It is also a good idea to make a back up of the program before making a repair like this. A back up can be made on a SD card or a PC if your have the software and cable.