T+A PA 2500 R Betriebsanleitung Seite 61

No output signal at the
loudspeakers; The display
shows "short L" or "short
R" 
No output signal at the
loudspeakers; The display
shows "overheat" 
Flat sound image,
insufficient bass response.
Machine switches itself off
automatically.
Cause:
Short-circuit in the speaker leads, e. g. stray wire ends touching at the speaker
terminals, or mechanical damage to the cables.
Remedy:
Check speaker leads and terminals, twist wire ends together neatly, replace
damaged cables.
Cause:
The PROTECTION circuit has tripped due to overheating.
Remedy:
Reduce volume and wait for about 20 seconds. If the unit does not switch on
again automatically, it has become too hot and should be left switched off for a
few minutes to cool down.
Cause 1:
Overheating due to heat build-up.
Remedy:
Set up the unit in such a way that an unobstructed flow of cooling air is
guaranteed.
Cause 2:
Overheating through insufficient loudspeaker impedance.
Remedy:
Use only loudspeakers of at least 4  impedance (DIN rating). That means a
minimum impedance of > 3.2 .
Cause:

The loudspeaker cables are connected with reversed polarity.
Remedy:
Check the speaker connections at the loudspeakers and at the integrated
amplifier's speaker terminals; correct if necessary.
Cause:
The Trigger function is set for a listening source, but the signal is not present.
The machine switches itself off after thirty seconds if the trigger signal is not
delivered.
Remedy:
Check the Trigger function setting in the Configuration menu, and switch it off if
appropriate.
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