Mallinckrodt Nellcor N-20 Service Manual page 24

Troubleshooting
201–203
4.7.3 Category 3 — PROM Errors
Errors in PROM memory (main PCB). Likely action is replacement of the PROM.
301
4.7.4 Category 4 — I/O Port Errors
Errors in the CPU's internal I/O port (main PCB). Likely action is replacement of either the CPU or
the main PCB.
401–409
4.7.5 Category 5 — Reserved
4.7.6 Category 6 — Clock Errors
Failure of the real-time clock (auxiliary PCB), or timing differences between the CPU's clock and the
real-time clock. Likely action is replacement of the main or auxiliary PCB.
601
602, 603
4.7.7 Category 7 — Watchdog-Timer Errors
Error in the watchdog-timer circuit of the CPU (main PCB). Likely action is replacement of the CPU.
701, 702
4.7.8 Category 8 — Printer Errors
Error in the printer (see Section 5.1, Troubleshooting).
If a printer error condition occurs, no error code number will display, rather the display reads Pr Err.
4-8
Errors in external RAM test
Error in PROM test
Errors in I/O port test
Failure of real-time clock
Errors in real-time clock
Errors in watchdog-timer