290
AR Area
Address(es)
Function
1901
FM Data Transfer Flag
1903
FM Blocks Different Error Flag
1904
FM Write-protected Error Flag
1905
Unsuccessful FM Write Flag
1906
FM Checksum Error Flag
1907
File Memory Unit Low Battery Flag
2400 to 2403
Leftmost digit of FALS-generating address (AR 25
contains the other four digits)
2500 to 2515
Rightmost four digits of FALS-generating address
(AR 2400 to AR 2403 contain the fifth digit)
8-6
Troubleshooting
The following tables provide basic hardware and software troubleshooting in-
formation.
CPU
Symptom
Possible cause
Correction
Power Supply does not turn on.
Voltage selector terminal setting error
Connect the voltage selector terminal
correctly.
Fuse is blown.
Replace fuse.
Fuse blows repeatedly.
Voltage selector terminal setting error
Connect the voltage selector terminal
correctly.
Circuit board is short-circuited, or
burnt.
Replace CPU Rack Power Supply
Unit or Backplane.
RUN indicator does not light.
Start input is OFF.
Turn the start input ON.
g
Programming error
Correct the program.
Power line is defective.
Replace CPU Power Supply Unit.
RUN output does not turn ON.
Power circuit is defective.
Replace CPU Power Supply Unit.
I/Os following a particular I/O number
do not operate.
I/O bus is defective.
Replace Backplane.
Abnormal I/Os on Expansion I/O Rack
are in groups of 8.
I/O Connecting Cable is defective.
(Cable wiring is broken.)
Replace the I/O Connecting Cable.
g
p
I/O bus is defective.
Replace Backplane.
One I/O turns ON erroneously.
I/O bus is defective.
Replace Backplane.
All I/Os of a particular I/O Unit do not
operate.
I/O bus is defective.
Replace Backplane.
Troubleshooting
Section 8-6