MAAP Ground Fault Troubleshooting Guide Rev C.wpd Page 3 of 7
g. If there is less than 500K Ohms from earth ground to the conductor, divide the
circuit in half and re-measure until the resistive source is located.
NOTE: A Ground Fault condition on zone wiring can be caused by wire insulation
being exposed where the conductors are making contact with the conduit. It can be
also caused by faulty devices.
H. Repeat troubleshooting until all shorts are eliminated. Reconnect all field wiring
and begin testing again.
Part One: Troubleshooting the Main Panel
1. Remove ac power (do not remove or replace F2 fuse under power), then remove
battery power (F4 fuse) from the panel. (The fuse is located in the top left hand
corner of the M Panel power supply board)
2. Ensure panel is powered down. Disconnect the ribbon cable from J6 on the main
board, this is the cable that connects to the backplane(s). Do not remove or replace
ribbon cable from CPU or backplane with ANY power applied.
3. Apply ac power and re-insert fuse F4. Acknowledge the troubles (COM fails) that
occur because of the disconnected backplane(s).
4. Wait for five minutes to see if the ground fault condition returns. If no ground fault
occurs go to Part Two: Troubleshooting the Backplane and Zone Expansion Cards
(ZEC). If the ground fault recurs, remove ac power and fuse F4 and proceed to
step 5.
5. Ensure panel is powered down. Remove all SLC field wiring from the AAC by
unplugging from each port. Unplug the printer, the remote terminal, and Remote
Display Units (RDU) from the AAC. Apply ac power and re-insert fuse F4.
Acknowledge the troubles (COM fails) that occur because of the disconnected
backplane(s). Wait five minutes to see if the ground fault condition returns. If no
ground fault occurs go to Part Three: Troubleshooting the Analog Addressable
Controller (AAC) and Analog Driver Card (ADC). If the ground fault recurs, remove
ac power and fuse F4 and proceed to step 6.
6. Ensure panel is powered down. Remove and label all remaining field wiring
EXCEPT: Auxiliary Power and RS-422 to the AAC. Remove individual wires from
the terminal block for (Auxiliary Inputs, and Zone 1) leaving RS-422 connected to
AAC. Remove Zone 2, Bell 1 & 2 by unplugging two-piece connector. Remove and
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