JRC JMR-92 Series Field Service Manual page 846

4.
Operate the keys, buttons and dials in the operation unit.
If the performance of the operation unit is normal, the colors of the keys, buttons and dials
are changed.
5.
Click on the [Key Test Stop] button after the performance check.
Returns to the "Diagnosis" dialog box.
7-23 Chapter 7 Troubleshooting