Table 5-5: Switches/Knob Problems - Mallinckrodt NELLCOR NPB-4000 Service Manual

Table 5-5: Switches/Knob Problems

Condition
1. NPB-4000/C fails to
power-up when
On/Standby switch is
pressed.
2. NPB-4000/C powers-
up, but some or one of
the other switches
respond.
3. When knob is rotated,
no highlight appears on
display screen, and/or
monitor does not
respond to knob
presses.
Section 5: Troubleshooting
Recommended Action
1. Take steps as noted in paragraph 5.6.1.
1. Ensure keypad is plugged into Main PCB. If
connection is good, change keypad.
2. If problem persists, change Main PCB.
1. Ensure encoder cable is plugged into Main
PCB. If connection is good, change
encoder.
2. If problem persists, replace Main PCB.
5-7