Problem Possible cause Possible solution
Amplifier: Fault light lit for
approx. one second.
– This is indicating
protection on that
channel (overload or
short condition).
– The amplifier
automatically retries the
channel after this time (1
min).
– Note that the amplifier
will not detect a short-
circuit directly without
signal - for instance, if a
short is on the output,
but no signal is being
driven, the amplifier may
not actually be in fault
mode. As soon as
enough signal is present
to activate the current
protection the fault LED
will light.
Amplifier: Fault LED flashes
quickly for around 30
seconds.
– This indicates a thermal
error on the channel.
– The channel will be
re‑activated after it has
cooled down.
Amplifier: Fault LEDs flash
slowly.
– This indicates that the
PSU has failed (or
thermally cut‑out).
– Send immediately for
service and/or contact
the Bosch authorized
dealer or installer for
assistance.
Call stations / Wall Control
Panel's LED keep rotating.
– RS485 ID cannot be
identified.
– Check that the switches
have been full switched
to the appropriate
positions, and reset
power to the unit.
– Check that the CAT‑5
cable is not damaged in
anyway.
– Download and connect
with the latest version of
PC GUI and check the
RS485 status "Device >
RS486 device status".
42 en | Troubleshooting PLENA matrix
2013-06 | V1.0 | Operation manual Bosch Security Systems B.V.