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EN 152
9.
Timing
When the transmission of AC3 surround signals is ended (e.g.
television 'off'), the mute line from the receiver becomes 'high'
and mutes the amplifier via TS7415. At the same moment, the
output of 7405 becomes 'low'. Now, capacitor 2407 starts
discharging into R3432. When the voltage on the positive input
of the comparator becomes lower then the voltage on the
negative input, the output of the comparator turns from 'high' to
'low' and the relay is switched 'off' by 7414. The established
time is 11 until 15 minutes (RC-time R3432/C2407). If the mute
line turns 'low' during this discharge period, the capacitor 2407
is charged again and the complete timing is reset.
Wired Backup
When there is no possibility to use the wireless link (due to
perturbations or interferences), it is possible to use a 'wired'
backup solution. On the rear of the box is a backup input. By
plugging in a cable with 3.5 mm stereo jack (order under nr.
3104 311 02251), the power supply for the receiver is
interrupted. The audio signal enters the amplifier now via this
backup input. An audio detector (7404) is added on the
amplifier board, to obtain the same functionality when we use
the wired backup.
The level detector (7405) is then triggered by the output of the
audio detector, i.s.o. the mute line coming from the receiver.
LED control
TS7410 and 7411 control the red or green part of a bicolour
LED, according to the voltage on the collector of TS7414.
9.6.3
Power Supply (Diagram W2)
The box can operate in two different modes: 'standby' and
'active' mode.
•
In the standby mode all power is delivered by a so-called
standby SOPS. This is a self-oscillating power supply,
which can deliver 12 V
timing circuitry. The delivered current in the standby mode
is rather low, mainly because the receiver board has a
'sleep' period of 3 seconds, and a 'listen' period of 0.2 s.
•
In active mode (relay 'on'), the main transformer bypasses
the standby supply, and all the needed power is now
delivered by this transformer (via diodes 6405-6406 and
capacitor 2401). This is done to reduce dissipation in
standby mode.
SOPS standby supply: a stable output voltage of 12 V
obtained by use of a low-drop voltage regulator L4940V12. The
feedback is formed with components R3201, 3204, 3205,
3206, and an optocoupler.
At primary side, there is a rectifier part that produces 350 V
(items 6206 and 2207). The SOPS is formed by the FET 7207,
transformer 5204, current-limiter 7206, 6205, and 6210, a
control circuit (7204, 7205, and 6207) and an optocoupler
(7203). The whole system works always in 'burst' mode. When
a higher current is necessary, the burst period becomes larger,
and the burst-repeat frequency increases. The SOPS can
operate on mains voltages between 90 and 264V
When the output voltage rises above 20 V
a fault in the feedback system of the SOPS), the circuit around
thyristor 6211 short-circuits the SOPS output. This gives a
reliable protection for the whole circuit.
MG3.2E
Circuit Descriptions, Abbreviation List and Data Sheets
for the receiver board and the
DC
DC
.
AC
, (e.g. caused by
DC
9.7
Abbreviation List
16:9-ARFRONT
50Hz/60Hz
6-CHANNEL DAC
ADC
AFC
AGC
AM/FM
AM-SOUND
AUDIO_C
AUDIO_L
AUDIO_R
AUDIO_SL
AUDIO_SW
AUDIO-L-PROC
AUDIO-R-PROC
AUDIO-SR
AUX-SUPPLY
BC-PROT
BG
BLC-INFO
B-SC1-IN
B-SC2-IN
B-TXT
B-vc
C
C/16/9
C-7-OUT
CENTER
C-FRONT
CL_DS_L
CL_DS_R
CL_L
CL_L_OUT
CL_R
CL-R-OUT
CODEC
COMP
ComPair
CORDL_L
CORDL_R
CORE TOP LEVEL
CRT
CSM
is
C-UI
CVBS
CVBS_Y-UI
DC
CVBS-PIP-DS
CVBS-SC1-IN
CVBS-SC2 OUT
CVBS-SC2-IN
CVBS-SC3-IN
CVBS-SC4-IN
CVBS-TER
CVBS-TXT-DS-OUT
CVBS-TXT-OUT
CVBS-Y-FRONT
D/K
DAC
DAC-HOP
DC_PROT/
AUDIO_SR
DC-filament
DC-PROT
DETECT
DFU
DIG_IN1
DIG_IN2
16:9 aspect ratio input from side I/O
50Hz/60Hz mains frequency
6- Channel DAC
Analogue to Digital Converter
Automatic Frequency Control
Automatic Gain Control
Amplitude Modulation/Frequency
Modulation
Amplitude modulated sound signal
Audio Centre
Audio Left
Audio Right
Audio Surround Left
Audio Subwoofer
Audio Left Processed
Audio Right Processed
Audio Surround Right
Auxiliary supply
Beam Current Protection
System B and G
Black Current Information
Blue SCART1 in
Blue SCART2 in
Blue teletext
Blue from video-controller
Centre
Chrominance input
Chrominance on pin 7 SCART
(variant)
Centre speaker
Chrominance front input
Constant Level Dual Screen Left
Constant Level Dual Screen Right
Constant Level Left
Constant Level Left out
Constant Level Right
Constant Level Right out
Coding/Decoding
Compander ON/OFF
Computer aided rePair
Cordless Left
Cordless Right
Core Top Level
Cathode ray tube
Customer Service Mode
Chrominance UI
Composite Video Blanking and
Synchronisation
CVBS Y UI
CVBS Picture In Picture dual Screen
CVBS SCART1 in
CVBS SCART2 out
CVBS SCART2 in
CVBS SCART3 in
CVBS SCART4 IN
CVBS terrestrial
CBVBS Teletext Dual Screen out
CVBS Teletext out
CVBS Luminance front input
Monochrome TV system. Sound
carrier distance is 6.5 MHz
Digital Analogue Converter
Digital Analogue Converter HOP IC
DC protection (for supply)
Filament supply voltage
DC protection
Detect signal side I/O input
Directions For Use: description for the
end user
Digital In 1
Digital In 2
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