7.
Troubleshooting
7.1
Electricity
Function
WA 9xx / 020:
Low supply voltages
8 V and ±15 V
WA 9xx / 020:
Connect the sensors to the sensor cables
3 8
Nominal state
On the power supply unit PCB 1 987 009
AE0N, ...AE7N, ...AG4N, there are three
LEDs which illuminate, if the supply voltage
exists.
When connecting the sensors via the sen-
sor cables, these are fed with a supply
voltage. Then, the LED (B) on the operator's
panel will illuminate.
What to do, if:
No LED illuminates:
Check the primary fuses on the PCB 1 987
009 AE0N, ...AE7N, ...AG4N.
If other components fail also check the fuses
on the electric distribution.
Only one or two LEDs will illuminate:
Check the corresponding secondary fuse on
the PCB 1 987 009 AE0N, ...AE7N,
...AG4N.
Re-measure the corresponding output volta-
ges:
Pin 1:
+15 V
Pin 2:
GND
Pin 3:
-15 V
Pin 4:
+ 8 V
No fuse defective:
Repair or replace PCB 1 987 009 AE0N,
...AE7N, ...AG4N (as from FD 04/03). As
from FD 04/03, compatible replacement
PCB 1 987 009 AG4N
No sensor function:
Check or replace sensor cable.
Plug sensor cable into the opposite socket.
Re-measure supply voltage via a multi-meter
at the sockets or at the plugs.
Pin 1:
-15 V
Pin 2:
+15 V
Pin 3:
N.C.
Pin 4:
TxD
Pin 5:
RxD
Pin 6:
N.C.
Pin 7:
N.C.
Pin 8:
N.C.
Pin 9:
GND
Pin 10:
N.C.
Pin 11:
+8 V
Pin 12:
GND
Alternately, voltages can be checked with
the diagnostic adapter 1 987 009 A31N.
Check whether the plug has been con-
nected correctly to the power supply unit
PCB.
22.01.04
1 689 975 177N