Vingtor Stentofon VPA-120, Инструкция по установке и обслуживанию

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Page 12 Installation and Service Manual A100K10876
VPA Amplifiers
5 SERVICE
5.1 Service information
z
All service on this unit should be performed by qualified service
technicians only.
z
Contact your local VINGTOR / STEENHANS dealer or their
representative for service.
z
Schematic diagrams, component layout, spare part lists and other
service information are available from Zenitel Marine.
WARNING! Always disconnect the mains cable and 24 VDC power before
opening the cabinet to avoid electrical chock hazard and
possible damage to the equipment
.
5.2 Troubleshooting
Low volume or distorted sound
z
Check that all input- and output connections are properly made
z The problem occurs from both inputs:
-
Check that the loudspeaker impedance corresponds with the
amplifier output.
z Distorted sound:
-
The amplifier may be overdriven. Turn the input level control(s) to a
lower level until the distortion disappears. Compensate the volume
loss by turning the master volume up.
z Problem on one input only:
-
Swap the two input sources. This will indicate whether the source
or the input channel is faulty.
A pulsating noise in the loudspeakers
A “motorboat” like sound during music and/or announcements. The
Overload lamp may light or flash.
z
The sound level is too high, attempting the output to exceed its limit.
-
Reduce the master volume control until the “motorboating”
disappears. Reducing the BASS control may also solve the
problem.
-
Be sure the VU-meter is not in the red area.
-
Re-adjust the input level controllers if needed.
The FAULT warning lamp is on
z
If the sound in the speakers are weak or absent,
-
Check the master volume setting, normally >40%
-
Check for shorted speaker line
z
If the sound seems normal, perform the pilot tone adjustment. See
section 4.1.3
The first green LED in the VU-meter is constantly on
It is normal that the -18 dB indicator just glows even if no external signal
source is active. The reason is the 23 kHz fault detection pilot tone.
z
If the light is bright, the pilot tone volume may need adjustment. See
section 4.1.3
The amplifier does not operate. The Power LED is not lit
z
Check the mains fuse F101 just under the mains cord.
z
Check the internal voltage fuse F501.
Open the cabinet and locate the fuse on the Power Rectifier board.