T+A Elektroakustik PA 820 M - Handbuch (Seite 52)

52
Trouble-shooting
Many problems have a simple cause and a corres-
pondingly simple solution. The following table describes
a few difficulties you may encounter, and the measures
you need to take to eliminate them.
If you find it impossible to solve a problem with the help
of these notes, please disconnect the unit from the mains
and ask your authorised
    specialist dealer for ad-
vice.
Protection
The Protection circuit provides outstandingly effective
protection against virtually all forms of overloading. This
it does by comparing the input signal before the output
stage with the output signal; if there is the slightest
discrepancy, the Protection circuit switches off the equip-
ment immediately.
This system protects the loudspeakers very effectively
against serious damage caused by clipping or other
signal-distorting errors.
The system also includes protective circuits which guard
against short-circuit and overheating. If a problem
occurs, the output signal is switched off and the loud-
speaker code letters ('
A A A A ' und ' B B B B ') on the integral screen
start to flash.
If this should happen, reduce the amplifier’s volume level
immediately!
After about 20 seconds the amplifier will normally switch
itself on again, and the code letters will cease flashing.
If the amplifier does not come on again after this period,
there may be a short-circuit in the loudspeaker cables, or
the amplifier may have become too hot; in this case it
should be left switched off for a longer period to cool
down.
Problem Table
Problem: Machine does not switch on (green LED
stays dark).
Cause: Mains lead not connected correctly.
Remedy: Check connection, push in firmly.
Problem: Machine does not respond to controls.
Cause: M LINK cable not connected correctly.
Remedy: Check connection, push in firmly.
Problem: System responds correctly to the front
panel buttons, but does not react to
remote control commands.
Cause 1: Batteries in remote control handset ex-
hausted, or fitted incorrectly.
Remedy: Fit new batteries, or re-fit batteries with
correct polarity.
Cause 2: No visual contact between system and
remote control transmitter (handset).
Remedy: Ensure direct visual contact between
remote control handset and receiver (glass
doors may prevent contact). Maximum
range between transmitter and system
approx. 6 metres.
Position the system so that the sensor in
the integral screen is not subject to direct
sunlight or excessively bright lighting.
Fluorescent lamps and energy-saving
bulbs are powerful sources of interference.
Cause 3: M LINK lead not connected correctly.
Remedy: Check connection, push in firmly.
Cause 4:
The RC address of the remote control
handset or the M-system is not set
correctly.
Remedy: Set the remote control handset and the M-
system to the same RC address (see
section 'F6 remote control handset -
switching the remote control address').
Note: The F6 remote control handset must
always be set to the same RC address as
the M-system.
Problem: Other items of equipment (Hi-Fi, TV,
VCR etc.) respond to the RC commands
from the F6 remote control handset;
alternatively the M-system responds to
the RC signals intended for other equip-
ment.
Cause: Overlap with remote control codes used by
other manufacturers.
Remedy: The F6 RC handset and the M-system
must be switched to a different remote con-
trol address (see section 'F6 - switching
the remote control address').