Crown MT-BB User manual

100501-1
8/96
Printed on
recycled paper.
MT–BB
© 1996 by Crown International, Inc., P.O. Box 1000, Elkhart, IN 46515-1000
U.S.A. Telephone: [phone]. Fax: [phone]. P.I.P. modules are
produced by the Professional Audio Division of Crown International, Inc.
Trademark Notice: CSL ™ is a trademark and Crown
®and
Micro-Tech
®are
registered trademarks of Crown International, Inc. Other trademarks are the
property of their respective owners.
MT-BB
–+–+
CH-2 INPUT CH-1 INPUT
ForTechnicalSupportcontact:
CrownAudioDivisionTechnicalSupportGroup
Plant2 SW, 1718W. Mishawaka Rd.,Elkhart, Indiana 46517U.S.A.
Phone: [phone] (North America, Puerto Rico and Virgin Islands) or 219-294-8200
Fax: [phone] Fax Back: 800-294-4094 (North America only) or 219-293-9200
Internet:http://www.crownintl.com

Page 2
MT–BB
Fig. 1.1 MT-BB
Fig. 1.3 Unbalanced Input Wiring
MT-BB
–+–+
CH-2 INPUT CH-1 INPUT
1 Welcome
The MT–BB Accessory Panel is de-
signed to give your Micro-Tech
®,
Power Base or CSL
™amplifierbarrier
block type inputs for permanent
installatons. Installing it requires the
accessof the top side ofthe Main Cir-
cuit Board and should only be at-
temptedby a qualified technician.
The barrier block connector is wired
as follows:
– NegativeInput
(inverting)
SignalGround
+ PositiveInput(non-
inverting)
Bothbalanced and unbalanced input
wiring are shown in Figures 1.2 and
1.3 opposite. Please note the jumper
between pins 1 and 3 when connect-
ing an unbalanced line to the input.
–+–+
CH-2 INPUT CH-1 INPUT
Fig. 1.2 Balanced Input Wiring
–+–+
CH-2 INPUT CH-1 INPUT

Page 3
MT–BB
FRONT
BOTTOM VIEW
MAIN BOARD
REMOVE SCREW REMOVE SCREW
3. Lay the amplifier upside down and
remove the bottom cover (8 phillips
screws).
4. Locate the Main Board (Figure 2.1)
and remove the two phillips screws
thatsecureitto the chassis.Remove
the nuts that secure the input phone
jacks to the rear panel. Lift the front
ofthe MainBoardto clear the stand-
offs.SlidetheMainBoardtowardthe
front until the phone jacks and level
control shafts clear the rear panel
thencarefullylifttherearoftheboard
to expose its top side (Figure 2.2).
Fig. 2.1 Inside an Amplifier
WARNING: TO PREVENT
ELECTRIC SHOCK, THIS
ACCESSORYSHOULD
ONLY BE INSTALLED BY
QUALIFIED SERVICE
PERSONNEL.
2 Installation
CAUTION: The MT–BB should only
be installed by qualified service per-
sonnelinthe following manner:
1. Turn down the level controls (full
counterclockwise),turn offtheampli-
fier and unplug it from the AC power
source.
2. Remove the filter/grille from the front
panel (3 phillips screws). Remove
therearcoverplateon the rear panel
(2 phillips screws).

Page 4
MT–BB
5. Insert the cable of the MT–BB
through the rear panel opening, and
throughtherectangularchassishole
directlybehindthe fan.
6. Plugthe MT–BB connectorintoJ1on
the Main Board. J1 is the five-pin
header located immediately behind
the Ground Lift Switch. The wires at
the connector should face the rear
withthe black wire on theleft and the
green wire on the right.
7. Fastenthe MT–BB panelin place us-
ing the screws provided and reas-
semble the amplifier by reversing
steps 4 through 2.
IMPORTANT: Check that no wires
impede the fan rotation.
8. Restore power to the unit and read-
justthe level controls.
Fig. 2.2 Installing an MT-BB
FRONT
BOTTOM VIEW
J1
ROUTE THE MT-BB CABLE
THROUGH THE RECTANGULAR
HOLE BEHIND THE FAN.
MT-BB
J1
BLACK GREEN
IMPORTANT:
DO NOT
INSTALL THE
CONNECTOR
UPSIDE DOWN.