SERVICE MANUAL
LBB 3310/00, 3330/00 and 3331/00 page: 14 Date of issue:
4822 861 11006 July 1998
10.2.4 Supply current measurement
Measure the supply current from V+ by means of a current meter in the power supply line itself: this should be between
30mA and 40mA.
K2 X10
1,2,3 V+
3
4,5,6 V-
1
Power Supply
PCB
CPSU
90 ... 264V AC / 24V DC
~
~
A
A1
+-
003_001.cdr
Figure 1
10.2.5 AUDIO-CONTR to Loudspeaker circuit
Noise level
Measure first the noise, A-weighted & rms, from the loudspeaker-signal between (symmetrical) M57 and M59 (see figure
2):
Noise level (A-weighted): < -70dBV.
629548 27
25Ω
X205
M59
X150X110
X10
AC
24V DC
Power Supply
90 ... 264V AC
~~
Loudspeaker
PCB CPSU
M110 M111 M121 M122 M124 M150 M151
M57
(GND) (GND) (GND)
003_002.cdr
LR IN
Rec-INLine-IN Rec-IN Telephone
+
-
A1
V
Figure 2
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