Nellcor OxiMax NPB-40 Service Manual page 44

Troubleshooting
Condition
• The CPU PCB is defective.
The display backlight does not come on when the
• The
Backlight
panel keypad is defective.
• Flex circuit between the front panel and
the CPU PCB is disconnected.
• A CPU PCB Component has failed.
• CPU PC has failed.
• The
Backlight
PCB have failed.
The NPB-40 shuts off when the
• The batteries are at or near a voltage too
low for the NPB-40 to operate.
The printer does not print.
• The printer and the NPB-40 are not
properly aligned.
• The printer is turned off.
• The bottom on the front panel
Data
keypad is defective.
36
Table 3:
Troubleshooting Guide
Recommended Actione
Replace the CPU PCB with a known good PCB. See CPU
PCB or Display PCB Replacement on page 46.
bottom on the front
Open the NPB-40, disconnect the front case from J3 on the
CPU PCB and connect an ohmmeter lead to the flex circuit
conductor for J3, pin 3 and individually connect the other
ohmmeter lead to each conductor for the buttons. Refer to
the front panel schematic diagram (**). Observe a short
when the button is pressed and an open when the button is
not pressed.
If incorrect, replace the front case. See Front Case Assembly
Replacement on page 49.
If correct, replace the CPU PCB. See CPU PCB or Display
PCB Replacement on page 46.
Inspect the flex circuit and reconnect if the flex circuit is
loose. See Separating the Front and Back Cases on page 44.
Inspect the CPU PCB components and circuit board for
cracking, burning, or damage and replace the CPU PCB if
any are found. See CPU PCB or Display PCB Replacement
on page 46.
Replace the CPU PCB with a known good PCB. See CPU
PCB or Display PCB Replacement on page 46.
LEDs on the Display Replace the Display PCB with a known good PCB. See
CPU PCB or Display PCB Replacement on page 46.
Backlight
Install new batteries. See the NPB-40 Operator's manual.
Align the printer and the NPB-40. See the NPB40
Operator's manual.
Turn the printer on. See the printer documentation.
Open the NPB-40, disconnect the front case from J3 on the
CPU PCB and connect an ohmmeter lead to the flex circuit
conductor for J3, pin 3 and individually connect the other
ohmmeter lead to each conductor for the buttons. Refer to
the front panel schematic diagram (**). Observe a short
when the button is pressed and an open when the button is
not pressed.
If incorrect, replace the front case. See Front Case Assembly
Replacement on page 49.
If correct, replace the CPU PCB. See CPU PCB or Display
PCB Replacement on page 46.
(Continued)
button is pressed.
Backlight
Caution: Unlock J3 before attempting to
remove flex circuit conductor.
button is pressed.
Caution: Unlock J3 before attempting to
remove flex circuit conductor.