Miles Technology Multisonic M44, Руководство по эксплуатации

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5 Troubleshooting Guide
26
5 Troubleshooting Guide
System Problems
No output
One loudspeaker channel is
not functioning
The system is noisy
Noise in the surround
channels
Hum or buzz in the system
Check if the Power indicator is on. If not, check the power
supply connection and make sure the ac outlet is on. If the
Power indicator is on, then check the Level controls and all input
and output connections. If everything seems to be in order, and
there is certainly an input signal, but there is still no output, call
customer service.
Press both Setup switches to provide an equal signal to all main
(left/center/right) outputs. If this seems to solve the problem (all
outputs are now equal), then verify that both left and right input
signals exist and are at the desired level. If not, check that the
power amplifier is operating and all the output cable connections
are correct. Check all the control settings of all equipment in the
signal path after the Imager.
Turn down the Input Level controls on the M86. Does the noise
go away? If not, the power amplifier gain is probably too high. If
the noise does go away with the Input Level down, the noise is
in the program source. Be sure the gain structure is correct
throughout the system.
As above, check the gain structure, and make sure there is not
too much amplifier gain. Does the noise goes away when the
Surround Output Level control is turned down? If so, then the
program source is probably noisy.
Also be sure you have a stereo source; there will be no
surround signal with a mono source.
Turning down gain controls while going backwards in the signal
path is a quick way to localize the source of hum. Start with the
power amplifier and go back in the signal path until turning
down an input or output gain control does not eliminate the hum.
If there is no gain control then instead disconnect the input
connection from each piece of equipment. When disconnecting
the input, or turning down the input or output does not eliminate
the hum, the source of the problem is at that or the following
piece of equipment.
Hum or buzz is usually caused by a ground loop from the use of
an unbalanced connection or a piece of equipment with a “pin 1
problem”. In either situation, shield current noise (which is
usually hum or buzz) is added into the audio signal. Be sure that
all equipment is correctly grounded. If both the Imager and the
other equipment have their chassis grounds connected to the
ac-line safety ground, then pin 1 at an XLR connection may be
lifted (i.e. opened, or not connected) at one end of the cable.
This should be done at the cable which when disconnected
causes the hum to stop. This will remove the shield current from
the signal connection.
Another possible cause of hum is a very strong magnetic field
near the Imager or other signal-processing equipment. For
example, this could happen if any line-level equipment is very