An optocoupler is used to control the regulation of line voltage and stand -by power consumption. There
is a regulation circuit in secondary side. This circuit produces a control voltage according to the
changes in 135V DC voltage, via an optocoupler (TCET 1102G) to pin3 of the IC.
During the switch on period of the transistor, energy i s stored in the transformer. During the switch off
period energy is fed to the load via secondary winding. By varying switch-on time of the power
transistor, it controls each portion of energy transferred to the second side such that the output voltage
remains nearly independent of load variations.
In Small Signal Board
V8Stby and +5V is switched by a discrete circuit to make power consumption effective.
? When supply switch port of ADOC IC is HIGH +5V ? 3.3V via IC103 regulator
? When supply switch port of A DOC IC is LOW V8Stby ? 3.3V via IC103 regulator
V8Stby is used to get +5V, which is available in Stby.
Supply Voltages Available/Not -Available In Stand -by, IC Requirement, Supply Location
Supply In Stby available? Where? For Which ? NOTE
135V (B+) NO large signal board FBT depends on
CRT
14V-A NO large signal board IC401,IC402(Audio
amplifier)
(-)14V-A NO large signal board IC401,IC402(Audio
amplifier)
14V NO large signal board Horizontal drive transistor
8V NO small signal board IC400 (MPIF)/Headphone discrete
circuit/RGB pre amplifiers/audio saw
filter(Z401)
5V NO small signal board IC400 (MPIF),Tuner(TU200,TU850)
V8stby YES large signal board Step down IC and for s+5V
1.8V YES small signal board IC313 (ADOC)
3.3V YES small signal board IC313
(ADOC),IC309(EEPROM),IC316(Reset IC)
12V NO small signal board CRT board (IC900)
5V YES small signal board LED/IR
Vert Sup+ (14V) NO large signal board Vertical IC (IC100)
Vert Sup- (-NO large signal board Vertical IC (IC100)
14V)
33V NO large signal board Tuner (TU200,TU850)
Important Microcontroller Ports For Supplying
Port State Function
On/Off low normal operation
On/Off high stand by mode
9.SERIAL ACCESS 64K EEPROM
M24C64WBN6, is the 64Kbit electrically erasable programmable memory. The memory is compatible
2
with the IC standard, two wire serial interface, which uses a bi -directional data bus and serial clock.
10.HEADPHONE AMPLIFIER STAGE
This stage is designed with discrete components (no IC is used for this purpose)
5
AK53 D.O.C. Service Manual 22/03/2004 |
ACEC
FUNAI
