Power Supply Control
The microprocessor part is supplied with 3.3V and 3.9 V both derived from the
‘MainAux’ voltage via a 3V3 stabilizer (7560) and a diode.
Two signals are used to control the power supply:
•
Stdby_con
This signal is generated by the microprocessor when over-current
takes place at the ‘MainAux’ line. This is done to enable the power supply into
standby burst mode, and to enable this mode during a protection. This signal is
‘low’ under normal operation conditions and goes to ‘high’ (3.3V) under ‘standby’
and ‘fault’ conditions.
•
POWER_DOWN
This signal is generated by the power supply. Under normal
operating conditions this signal is ‘high’ (3.3 V). During ‘standby’ mode, this
signal is a pulse train of approx. 10 Hz and a ‘high’ duration of 5 ms. it is used to
give information to the UOC about the fault condition in the Audio amplifier
supply circuit. This information is generated by sensing the current on the
‘MainAux’ line (using voltage drop across R3564 to trigger Q7562). This signal
goes ‘low’ when the DC-current on the ‘MainAux’ line exceeds 1.6- 2.0 A. It is
also used to give an early warning to the UOC about a power failure. Then the
information is used to mute the sound amplifier to prevent a switch off noise and
to solve the switch-off spot.
Protection Events
Several protection events are controlled byte UOC:
•
BC protection
, to protect the picture tube from a too high beam current. The UOC
has the capability of measuring the normal back level current during the vertical
flyback. So if for some reason the CRT circuit is malfunctioning (i.e. highbeam
current), the normal black current will be out of the 75 µA range, and the UOC
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Страница 14: ...AV2 In SVHS Connector Kind Value Symbol 1 gnd v 2 gnd v 3 Y 1 Vpp 75 O j 4 C 0 3 Vpp 75 O j ...
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Страница 20: ...Figure Panel Removal 1 Lift the board out of its bracket after releasing the 2 fixation clamps Figure ...
Страница 48: ...Hardware Alignments Figure Mono Carrier Top View LS ...
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Страница 106: ...All Models 7629 Power Supply Diagram A1 ...
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Страница 111: ...All Models 7629 Synchronization Diagram A6 ...
Страница 112: ...All Models 7629 Control Diagram A7 ...
Страница 113: ...All Models 7629 Audio Amplifier Diagram A8 ...
Страница 114: ...All Models 7629 BTSC Stereo SAP Decoder Diagram A9 ...
Страница 115: ...All Models 7629 Audio Video Source Switching Diagram A10 ...
Страница 116: ...All Models 7629 BTSC NDBX Stereo Decoder Diagram A11 ...
Страница 117: ...All Models 7629 Front I O Control Headphone Diagram A12 ...
Страница 118: ...All Models 7629 Rear I O Cinch Diagram A13 ...
Страница 119: ...All Models 7629 PIP Interface Diagram A16 ...
Страница 120: ...All Models 7629 CRT Panel Diagram B1 ...
Страница 122: ...USED ONLY IN MODELS 27PS50B321 32PS55S321 32PS61S321 32PS55S331 7629 Side AV and Headphone Panel Diagram E1 ...
Страница 123: ...USED ONLY IN MODELS 27PS60S321 27RF72S325 32PS61S321 7629 PIP Panel Diagram P ...
Страница 125: ...USED ONLY IN MODELS PC0125C321 PC0127C321 7629 EPS Panel Schematic ...
Страница 126: ...USED ONLY IN MODELS PC0125C321 PC0127C321 7629 Card Interface Schematic ...
Страница 127: ...USED ONLY IN MODELS PC0125C321 PC0127C321 PL0125C321 PLW225S321 PRF227S325 7629 SP LS Panel Schematic ...
Страница 128: ...All Models 7629 Main Panel component side ...
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Страница 137: ...All Models 7629 EPS Panel PCB Top View only ...
Страница 138: ...All Models 7629 Card Interface Panel PCB Top View ...
Страница 139: ...All Models 7629 Card Interface Panel PCB Bottom View ...
Страница 140: ...MAIN CABINET EXPLODED VIEW ...