Meyer Sound UMS-1P - Manuel (Page 9)

This section suggests several possible
solutions to problems encountered by
UMS-1P users, and is not intended to be
a comprehensive troubleshooting guide.
Please contact Meyer Sound for addi-
tional information and documentation.
T
HE
O
N
/T
EMP
. LED
DOES NOT ILLUMI
-
NATE AND THERE IS NO AUDIO .
1. Make sure the AC power cable is the
correct type for the regional voltage
and that it is securely connected to
the AC inlet, then unplug and recon-
nect the AC cable.
2. Check that the voltage selector
switch is set properly. If you need to
operate in the 100V range, be sure
you are using the 100V version of the
UMS-1P.
3. Use an AC voltmeter to verify that
the AC voltage is within the ranges
95-105V, 110-130V, or 220-240V.
T HE O N /T EMP . LED IS ILLUMINATED
BUT THERE IS NO SOUND
.
1. Verify that the audio source (mixer,
EQ, delay) is sending a valid signal.
2. Make sure the XLR cable is securely
fastened to the XLR audio input con-
nector.
3. Verify that the XLR cable is function-
ing by substituting another cable or
by using the cable in question in a
working system.
4. Send the audio signal to another
loudspeaker to insure signal presence
and that the level is within the prop-
er range. Turn the source level down
before reconnecting the audio input
and increase the level slowly to avoid
a sudden blast of sound.
5. If possible, monitor the audio source
with headphones.
Hum or noise is produced by
the loudspeaker.
1. Disconnect the audio input. If the
noise persists, the problem is within
the UMS-1P. In this case return the
unit to the factory or nearest autho-
rized service center. If the hum ceas-
es, the noise originates somewhere
earlier in the signal path.
2. Make sure the XLR cable is securely
fastened to the XLR audio input con-
nector.
3. Send the audio signal to another
loudspeaker to insure signal presence
and that the level is within the prop-
er range. Turn the source level down
before reconnecting the audio input
and increase the level slowly to avoid
a sudden blast of sound.
4. Hum or noise can be produced by a
ground loop. Since the UMS-1P is
effectively ground-lifted, the loop
must be broken elsewhere in the sys-
tem.
5. If possible, monitor the audio source
with headphones.
The audio produced by the
loudspeaker is distorted or
compressed but the limit light
is not illuminated.
1. Make sure the XLR cable is securely fas-
tened to the XLR audio input connector.
2. Send the audio signal to another
loudspeaker to insure that the level is
within the proper range. Turn the
source level down before reconnect-
ing the audio input and increase the
level slowly to avoid a sudden blast
of sound.
3. Monitor the audio source with head-
phones.
The audio produced by the
loudspeaker is highly com-
pressed and the limit light is
constantly red.
1. Turn down the level of the input sig-
nal to the loudspeaker system.
There is sound but it is does
not seem to be at full power
and the On/Temp. LED is red.
This occurs in conditions where the
heatsink temperature reaches 85°C
(185°F), indicating that the amplifier is
thermally overloaded. The limiter thresh-
old has dropped to a safe level, so the
audio level is reduced.
1. Make sure there is enough clearance
above, below, and behind the unit.
2. Make sure there is sufficient air flow
around the unit.
3. Avoid exposing the heatsink to direct
sunlight if the ambient temperature
is high.
See the Amplification, Limiting, and
Cooling System section on page 6 and 7
for a complete discussion of the cooling
system.
9
TROUBLESHOOTING