Open Fault - Bosch PRAESENSA Installation Manual

24 en | Troubleshooting
6.1.2

OPEN fault

LDB shows OPEN fault in following cases:
1.
2.
3.
Notice!
In case of T‑Branch fault (OPEN or SHORT), FIM will open both loop relays, isolating T‑Branch
i
and causing the loop OPEN fault on LDB. The FIM reporting T‑Branch fault will stay open until
the fault is still detected. To close the loop again, FIM reset is required after removing the
fault.
4.
Possible solution
1.
2.
3.
2021.07.28 | V1.00 |
Loop cable is open (L+ or L- or both wires).
Loop section between FIMs is isolated because of previously detected short circuit. See
SHORT fault, page 22 .
T‑Branch fault (OPEN or SHORT)
Power amplifier is disconnected.
Check if power amplifier is connected. If so, continue with the same procedure as for
SHORT fault. Two alternative solutions are available:
Loudspeaker line isolator Sniffer (PC application) is the easiest way to go. Use FIM
tracking feature for the best result. FIM tracking is automated procedure which allows
you to find the exact location of the open fault. Please, go to the loudspeaker line isolator
Sniffer manual for details. See
Disconnect loudspeaker cable from SECONDARY output of LDB and put an audio signal
in the zone including faulty loop. Loudspeaker line isolator will feed the loop with audio
signal only from PRIMARY side. While listening to loudspeakers follow the loop and find
first area (including T‑Branches) with no sound reproduction.
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Installation manual
Loudspeaker line isolator system
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