![Bosch LBB 1920 Installation And User Instructions Manual Download Page 19](http://html.mh-extra.com/html/bosch/lbb-1920/lbb-1920_installation-and-user-instructions-manual_37703019.webp)
Bosch Security Systems | 2006-11 | 9922 141 50751en
Plena Power Amplifier
| Installation and User Instructions | Operation
en
| 19
5
Operation
5.1
ON and OFF
5.1.1
Switch on
Put the
power
switch on the rear of the power amplifier
(see figure 5.1) in the
I
position.
If mains power or back-up power is available, the
VU-bar (1) on the front of the power amplifier is lit and
shows the output level of the amplifier (see figure 5.2).
If the internal temperature reaches a critical limit due to
poor ventilation or overload, an overheat protection
circuit switches OFF the power stage. The Overheat
indicator (5) shows on the front panel and a signal is
given on the Input fault relay if the power stage is
switched OFF by the overheat protection circuit.
The Battery operation indicator (3) lights up if the mains
power supply is failing and the back-up battery is in use.
5.1.2
Switch off
Put the
power
switch of the power amplifier (see figure
5.1) in the
O
position.
figure 5.1: Power switch
100V
0
100V
0
Priority C
ontrolled
Output
24V DC
In
Appara
tus deliv
ered
connecto
red for 23
0V~
Main
Power
Battery
t
elays' Outp
ut
NC
Off On
NO COM
NC NO
COM NC
100V
0
70V
0
8ohm
100V/70V
Selection(1
2A)
PriorityOn
ly
0
0
No Priority
Priority
F
7
0
1
F
7
0
2
Batter
y
Power
Detecti
on
230V~
240V~
Rated
input
Power :
1600VA
100V
70V
0
0
8
Direct O ut
put
100V
0
1 00V
0
Priority C
ontrolled
Output
Off On
24V DC
In
Apparatus
delivered
connecto
red for 23
0V~
Main Pow
er
Battery
Input
Fault Relays'
Output
NO COM
NC
Off On
NO COM
NC NO
COM NC
Input1Prio
rity
Loopthrou
gh 1
Input2Pro
gram
Loopthrou
gh 2
Input1Prio
rity
2...24V- In
put 1
0V- Input2
Input 2En
able
2..24V- En
able
0V- Mute
100V
0
Slave Inpu
t 100V
+
+
-
-
100V
0
70V
0
8ohm
100V/70V
Selection(1
2A)
PriorityOnly
0
0
No Priority
Priority
F
7
0
1
F
7
0
2
Battery
Power
Detection
Pilot-tone
Detector
230V~
240V~
Design &
Quality
The Netherl
ands
LBB 1938
/10
NL-4827H
G-10
Plena 480W
Power Am
plifier
Max. outp
ut power
720W
Rated out
put powe
r 180W
230V~,50
/60Hz
S/N.
8900 193
81001
A035413
M
a
d
e
in
C
h
in
a
N663
Rated inpu
t
Power :
1600VA
Input 1
P riority
S lave Inp
ut
100V
Input 2
E nable
100V
0
100V
70V
0
0
8
Direct O utp
ut
Input
Input
Input 2-Pro
gram
Input 1-Pr
iority
2..24V
Default O
ff
GND 2..24
V
Default O
n
GND
Line fus
e
T10L25
0V
figure 5.2: Front panel LBB1938/20
0 dB
-6 dB
-20 dB
Battery
Overheat
Mains
Pilot-Tone
Status
Plena
Booster Amplifier
1
3
4
5
2
6