JRC JMR-92 Series Field Service Manual page 642

Step 3 Check operation.
After the replacement of the keyboard is completed, turn ON the circuit breaker for the power
supply of the display unit and check the operation as follows.
(1) Check that a keyboard open error has not occurred.
(2) By referring to "7.2.3 Checking the Operation of the Operation Unit [Key Test]," check
that all the buttons and knobs of the KOPU respond normally.
(3) By referring to "7.2.5 Testing LED Brightness [Light Test]," check the brightness of the
LEDs.
This completes keyboard replacement.
4-421 Chapter 4 Replacement procedure