6
P
OWER UP AND TESTING
Before applying power, double check all the wiring
connections at the master, the amplifi er, and the volume
controls.
1. Complete any necessary installation of the Intercom
Master, its Room Stations, and accessories.
Install the master into its wall housing.
2. Complete any fi nish-out required for the volume
controls. Set each volume control to mid level.
3. Complete any fi nish-out required for the speakers.
4. Replace the amplifi er’s cover and tighten the cover screws.
5. Apply power to the Intercom Master. For testing, select
a strong FM radio station on the master. Verify that the
station’s audio is coming out of the master’s speaker.
6. Insert the female end of the 120 VAC line cord into the power
input plug on the bottom of the MC960PA amplifi er.
7. Plug the male end on the line cord into the wall receptacle
designated for the amplifi er. (In multi-amplifi er installations,
repeat Steps 4, 6, & 7 for the additional amplifi ers.)
8. When the amplifi er(s) is powered up, the radio station playing on
the master should also be playing on all the system speakers.
9. Go to each volume control and test the
performance at each speaker area.
T
ROUBLESHOOTING
If a problem is encountered after completing the installation,
refer to the following troubleshooting table for a guide to
correcting the problem.
TROUBLESHOOTING TABLE
SYMPTOM
SOLUTION
NO AUDIO OUTPUT
1. AC line cord not connected.
2. No 120 VAC power at AC outlet.
3. Verify that audio is playing at the master.
4. Check the audio input connectors on the amplifi er. Verify that the wire colors are correct and that the plug-in connectors are
fi rmly seated.
5. Check the audio output connector on the master. Verify that the wire colors are correct and that the plug-in connectors are fi rmly
seated.
6. Re-check all wiring per these installation instructions.
7. Check for a blown amplifi er fuse. If the fuse is blown the amplifi er was overloaded.
THE AMPLIFIER IS DESIGNED FOR
45-OHM SPEAKERS ONLY
!
DO NOT USE
8
-OHM SPEAKERS
!
Replace the fuse (lower right corner of circuit board, under a clear snap-on cover) with a 2 amp, 250 V, 5 x 20 mm, SLO-BLO®
fuse (Littelfuse® part number 218002).
AUDIO DISTORTION
1. Check for ground loops. Shielded cables should only be grounded (with the shield “drain” wire) at the source end.
2. Check for mechanical vibration at the speakers. Verify that the speaker mounting is secure and there is no loose hardware.
Check for wires or cables touching the back of the speaker’s cone.
3. Possible damaged speaker, swap with another and test again.
LOSS OF BASS
(STEREO ONLY)
1. Check for stereo speaker pairs wired out of phase (wires fl ipped on one speaker). Listen to the pair while moving from one
speaker to the other. An abrupt change from one speaker to the other indicates a possible phasing problem.
VOLUME CONTROLS INOPERATIVE
1. Check for a wiring error. Re-check all wiring per these installation instructions.
SHORTED POWER AMP
(HOT HEAT SINKS, DISTORTED
AND/OR LOW SOUND, THERMAL
SHUTDOWN)
1. Shorts to ground through shield drains at volume controllers or at the Power Amp (ensure shield drains are isolated).
2. Verify the speakers connected are 45-ohm speakers (8-ohm speakers can appear as a short).
3. Install only ten 45-ohm speakers per channel.
4. On the SVC96 (stereo volume control) install only 1 speaker per channel (one for left, one for right) –
MAXIMUM OF TWO
45-OHM SPEAKERS PER SVC96 STEREO VOLUME CONTROL.
5. On the MVC1 (monaural volume control) install only 1 speaker –
MAXIMUM OF ONE 45-OHM SPEAKER PER MVC1
MONAURAL VOLUME CONTROL.
IN
S
ERT LINE CORD INTO
POWER INPUT PLUG
Figure 13. AC Line Cord Connection
