D9412GV2/D7412GV2 | Troubleshooting Guide | 3.0 Troubleshooting
98 Bosch Security Systems, Inc. | 11/05 | F01U011024B
TTP46: Shorted Wiring
A
Initial Actions
IMPORTANT: The rest of this procedure uses a half-
split troubleshooting approach. By answering the
You must understand the devices and wiring splices
contained in the circuit you are troubleshooting. If you
do not know this information, trace the wiring as
required.
following question, you divide the circuit in half to
determine the half of the circuit that contains the short.
This half is the “affected circuit”.
By repeating the question, you divide the affected
circuit in half again to determine the half of the affected
If you are unsure of which circuit to
troubleshoot, refer to Section 4.1.4
Identifying Addressable Points on a Circuit
on page 116.
circuit that contains the short. That half becomes the
affected circuit.
Repeat the following question as many times as
necessary until you reduce the affected circuit enough
to identify the location of the short. Refer to Figure 56
on page 99.
Procedure
1. Disconnect the wire’s conductors from the control
panel or module.
During the rest of this TTP, if the TTP states “repeat
the process and question above”, return to this
2.
Set your digital voltmeter (DVM) to measure resistance.
location in the TTP.
3. Connect the red DVM lead to one conductor and the
black DVM lead to the other conductor.
Disconnect the middle device or splice in the affected
circuit.
For the remainder of this TTP, leave the DVM
Does the DVM indicate a short?
connected to these two conductors.
Is there more than one piece of equipment connected to
this conductor, or are there wire splices on the
conductor?
At the other end of the wire, cut and re-strip the
insulation from the wire and each conductor.
Does the DVM still indicate a short?
The short is corrected. Reconnect all
equipment on circuit.
The problem is either that the disconnected
equipment is faulty, or the conductor was not
connected to the equipment correctly. If the
problem returns after reconnecting the
equipment, replace the equipment.
Run the wire again, then reconnect all equipment on
the circuit.
If the devices on the circuit indicate operation status
(for example, LEDs that light), use those indicators to
determine the devices that are not operating. These
indicators help determine the location of the short.
A
Refer to
Figure 56 on page 99. The problem is
between where you disconnected the device or splice
and either:
-
the end of the circuit, or
- the location of the device or splice you
disconnected the last time the DVM indicated a
short.
Reconnect the device or splice, then repeat the
process and question above.
Refer to Figure 56 on page 99. The problem is between
where you disconnected the device or splice and either:
-
the DVM, or
- the location of the device or splice you disconnected
the last time the DVM indicated an open.
Reconnect the device or splice, then repeat the process
and question above.
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