TC12 Installation, Commissioning & Maintenance Handbook
Symptom Possible Reason
only one
Digital Output PCB of Digital Output PCB faulty
not connected
Digital Output PSU fuse blown/faulty
2.4.7
er Bs c
owered up. Disconnect the attached cables from the
CB, push down the latch on the front of the PCB guide and slide the PCB out of
the rack. Insert the new PCB and reconnect.
2.4.8 TC12 Instation PC Help / Diagnostic Screens
If a monitor is attached to the TC12 PC (note the TC12 Instation Test Set can be
used as the monitor) a number of Help/Diagnostic screens are available in the
TC12 PC Software. These are described below.
2.4.8.1 Help screen, Key to Press 'H'
This Screen lists all of the diagnostic and help screens and keys to be pressed to
activate them.
2.4.8.2 First 22 TC12 OTUs on an Instation, Key to Press '2'
This screen displays the replies received from the first 22 TC12 OTUs on an
Instation. It displays each OTU’s reply on a separate line on the screen, OTU 0 at
top. This screen only shows the first 22 OTUs on an Instation but can be used to
obtain indication of the health of the system.
The first eight digits on a line are characters indicating what errors were detected
with the particular OTU reply. The characters represent the errors as follows.
A = Address error
M = MT (message transfer) bit set in reply
N = No reply
S = Short reply
C = reply CRC error
P = parity error (not used in TC12)
F = framing error in reply
O = over run error on reply message
PSU to Digital Output PCB watchdog ribbon cable
faulty/not connected
Watchdog Fail LED ON for Watchdog ribbon cable faulty
several t Driven Watchdog Failure Digital Outputs No
Digital Output PCB fuse(s) blown
Incorrect/faulty wiring
Digital Output PSU
Replacing Modem, Transformer and Digital Output PCBs
The modem and transform
replaced whilst the rack is p and Digital Output PC an be removed and
P
666/HE/43100/000 Page 52 Issue 9