It is very common that the power switch in the Roland SH-101 becomes bad, which was also the case in my friend’s unit. This can cause various strange issues, the unit powers up as it should but when the button is touched various strange issues can occur. This can be resolved either by opening up the original switch and cleaning it or replace it with a new switch. In this case we decided to replace the switch with a new one.
The original switch is no longer possible to buy new. There is a suitable replacement available from some shops. I am not affiliated with any of these
The original switch has eight pins and the replacement one has six pins. This is not a problem as only four of the pins are used. The replacement switch should be mounted in the top six via holes closest to the power LED