MAAP Ground Fault Troubleshooting Guide Rev C.wpd Page 4 of 7
label individual wires for AUX OUT, K1 & K2 connections, and Remote Trouble,
noting polarity, from the main board, (leaving Auxiliary Power connected to AAC).
7. Apply ac power and re-insert fuse F4. Acknowledge all of the troubles that are
annunciated because the Backplane(s), On-Board Zones and Bell circuits have
been disconnected.
8. If the ground fault occurs remove battery cable and connection to the transceiver on
the CPU board, (P3). If the ground fault remains with all wiring disconnected, other
than ac power, contact Monaco Enterprises for a return authorization number for
the MAAP CPU and P.S.
9. If no ground fault occurs, perform the following:
a. Connect the field wiring to the main panel, one circuit at a time (Auxiliary Inputs,
Zone 1 and 2, Bell 1 & 2, Auxiliary Out, Auxiliary Power, and K1 & K2
connections).
b. Wait for five minutes to see if a ground fault occurs.
c. If a ground fault occurs, a ground fault condition exists in the field wiring that was
just connected and/or the devices connected to it. Correct the ground fault in the
field wiring. Note: A Ground Fault condition on zone wiring can be caused by
conditions such as 1) wire insulation being exposed where the conductors are
making contact with the conduit, 2) induced ac noise where the zone wire is run
next to or over ac power wiring, or 3) faulty devices.
Additional Troubleshooting: Disconnect the loop from the zone input. Measure the
resistance of each leg of the loop to earth ground. If a short to ground is detected, divide the
circuit in half and re-measure until the source of the short to ground is located.
If a short to ground cannot be detected check the wires for induced AC noise. Set the
DVOM to measure AC. Measure each leg of the loop to earth ground. Then measure
across the loop. If any of the AC measurements are 50 Millivolts, or above, the source of
the induced AC noise must be located. This normally occurs when AC and DC circuits
are run in the same conduit or twisted wire pair has not been used on the field wiring. To
reduce the AC noise, separate the wiring or install twisted wire pair and ensure all
conduit runs are bonded to earth ground.
d. If no ground fault occurs, then re-connect the next circuit.
