Mallinckrodt Nellcor N-20PA Service Manual page 35

Category 1 — Microprocessor Errors
Category 2 — RAM Memory Errors
Category 3 — PROM Errors
Category 4 — I/O Port Errors
Category 5 — Reserved
Errors in the CPU (main PCB). Likely action is replacement of the CPU.
101 Error in internal RAM register test
102 Error in zero register test
103 Error in register contents clearing test
104 Error in register contents increment test
105 Error in register contents decrement test
106–109 Errors in logical operations test
110 Error in exchange test
111 Error in timer tests
112 Error in window select register test
113,114 Errors in stack manipulation test
115–117 Errors in CPU flags test
118 Error in interrupt pending register test
119 Error in program counter test
120 Error in CPU serial port test
121 Error in pulse width modulation register test
122 Error in A/D register test
123 Error in addressing modes test
124 Error in high-speed input register test
125 Error in content addressable memory test
126–129 Errors in arithmetic operations test
Errors in RAM memory (main PCB). Likely action is replacement of the main
PCB.
201-203 Errors in external RAM test
Errors in PROM memory (main PCB). Likely action is replacement of the
PROM.
301 Error in PROM test
Errors in the CPU internal I/O port (main PCB). Likely action is replacement of
either the CPU or the main PCB.
401-409 Errors in I/O port test
Troubleshooting
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