COLOUR TV SET
Models:
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1 Technology Specification and Feature
2. The survey
Table 1, the main IC and functions
Number Function IC Remark
1 Power supply KA5Q0765RT N501
2 CPU + SIGNAL PROCESSER TDA93x1 N301
3 Field driver LA78040/STV9302A N401
4 Sound processor TDA9859 N122
5 Sound driver AN17821A N161
6 AV SWITCH TC4052BP N801 (Video)
7 Memory AT24C08 N702
8 Photo-coupler HS817B N504
9 IR-receiver HS0038A U701
10 8V Regulator L7808CV N503
11 5V Regulator L7805CV N505
3. The main chips instruction
1
. TDA93X1
T
he UOC (“Ultimate One Chip”) TDA93X1
is adopted in this chassis. This IC is the first available component that contains the complete
c
ontrol and small signal functionality needed for a TV application in one device.
T
he UOC TDA93X1 pins function description：（total 64 pins）
Pin1: Standby control,“ 1” is on,“ 0” is off.
Pin2: SCL.
Pin3: SDA.
Pin4: Tuning PWM output.
Pin5: Auto AV control SW/NTSC SW,
Pin6: Key board input.
Pin7: Volume
Pin8: Mute control,“ 1” is mute,“ 0” is off.
Pin9: Pin12、Pin18、Pin30、Pin35、Pin41、Pin55: GND.
Pin10: BAND1 control output.
Pin11: BAND2
Pin12: GND
Pin13: SECAM PLL, connected with a capacitance.
2
Pin14: +8V power source supply.
Pin15: Using a capacitor of 220n in series to GND, This pin decouples the internal digital supply
v
oltage of the video processor and minimizes the disturbance to the sensitive analogue parts.
Pin16: PHI-2 control loop, this pin requires a capacitor at 2.2nF (C) in series to GND.
Pin17: PHI-1 control loop, the loop filter connected to pin 17 is suitable for various signal conditions
li
ke strong/weak and VCR signal. This is achieved by switching of the loop filter time constant
b
y changing the PHI-1 output current.
Pin18: GND.
Pin19: Bandgap decoupling, the bandgap circuit provides a very stable and temperature independent
re
ference voltage. This reference voltage (4.0 V) ensures optimal performance of the analogue
v
ideo processor part of the N301 and is used in almost all functional circuit blocks.
Pin20: East-west pillow signal output.
Pin21: Pin22：Vertical drive output.
Pin23: Pin24：IF input。
Pin25: Reference current, This pin requires a resistor to ground. The optimal reference current is
100mA which is determined by this resistor. The 100mA reference current should not be changed
b
ecause the geometry processor is optimised for this current. Furthermore the output current of
v
ertical drive and EW are proportional to this current.
Pin26: Vertical sawtooth, This pin requires a capacitor to ground of 100nF
Pin27: AGC output. This output is used to control (reduce) the tuner gain for strong RF signals.
Pin28: Audio de-emphasis.
Pin29: Sound decoupling. This pin requires a capacitor connected to ground. The pin acts as a low
p
ass filter needed for the DC feedback loop.
Pin30: GND.
Pin31: Sound loop filter.
Pin32: AVL filter.
Pin33: Horizontal drive signal output, needs a resistor in series to +8V.
Pin34: Sandcastle output/flyback input,
Pin35: External audio input, this pin should be grounded in this chassis.
Pin36: EHT tracking/ overvoltage protection. If something is wrong, the anode high voltage rises, the
h
eater voltage will rise too. When the rising voltage arrive some limit, the VD461 works, the
v
oltage of pin 36 will exceed 3.9V, the N301will stop working.
Pin37: PLL loop filter.
Pin38: CVBS output. Monitor or RF videos can be selected.
3
Pin39: +8V supply source.
Pin40: CVBS input
Pin42: Y signal input.
Pin43: C signal input.
Pin44: Main audio output
Pin45: RGB signal input blanking.
Pin46, Pin47, Pin48: RGB signal input.
Pin49: ABL. It means been current limiter input. The R464 is the control resister.
Pin50: Black current input from the CRT board.
Pin51, Pin52, Pin53: RGB drive signal output to the CRT board.
Pin54: +3.3V.
Pin55: GND.
Pin56: +3.3V.
Pin57, Pin58, Pin59: 12MHz crystal。
Pin60: Reset, NC in this chassis.
Pin61: +3.3V
Pin62: This pin is connected to the HEF4052, Functions expanding.
Pin63: This pin is connected to the HEF4052, Functions expanding.
Pin64: IR signal input.
2 Memory AT24C08 is an E2PROM of 8k, pins describe as follows:
Pin1, Pin2, Pin3,Pin4, Pin7: GND. Pin8: +5V supply.
Pin5: SDA. Pin6: SCL.
3 HEF4052 is described as follows:total 16 pins
HEF4052 Pin9 HEF4052 Pin10 STATE
0 0 TV
0 1 AV
Pin8: GND.
Pin16: +5V supply.
4
4. Signal process
T
he main chip is N301 TDA93X1 AV control switch HEF4052, sound driver is N101
A
N17821A。
T
he TV signal inputs into the tuner (A101) from CABLE or antenna. The pin 10 and pin 11 of the
N301 are combined to select the band. The pin 4 of the N301 outputs the PWM tuning signal. The IF
video signal comes from the IF pin of the tuner. The 38.9MHz IF signal is coupled to the V308
(pre-amplify) and then to SAWF (Z301). After processed in the SAWF, the 38.9MHz signal gets to the
pin 23 and pin 24 of TDA93X1. The IF circuit in TDA93X1 includes such unit as the AGC amplifying
circuit, 38.9MHz oscillator, PLL video demodulator, video amplifier, IF identify circuit and AFT
circuit. The demodulated signal (CVBS) comes from the pin 38 of TDA93X1, the sound signal comes
from the pin 44.The internal CVBS signal needs norm identification then outputs from the pin 38 of
TDA93X1, via the trap-wave circuit (composed of the V351, Z354, Z352) feeds back to the pin 40 of
TDA93X1. The RGB signal comes from the pin51, Pin52, Pin53 of TDA93X1, and outputs to the
CRT board.
T
he internal sound signal comes from the pin 44 of TDA93X1, via the coupling capacitor C367
connects to the pin 3 and 5 of TDA9859. The TDA9859 is the audio effect processor, the AN7522N
is the driver. The TDA9859 includes bass, treble, balance, surround, effect shortcut options.
Through Synchronous separating circuit, the video signal is divided into
orizontal-Synchronizing signal and Vertical-Synchronizing signal. The horizontal-Sync pulse coming
from the pin 33 is ransferred to the horizontal-drive transistor, and will be used to drive the
horizontal-transformer. The horizontal-switch transistor is V451, it and the +B supply drives the
flyback transformer to generate the anode high voltage, the focus voltage, the screen voltage, the
CRT board drive voltage 180V, the vertical drive voltage 15V and -15V.
The vertical sawtooth wave is generated on the pin 21 and 22, and then enters the vertical output
amplifier circuit. The vertical output amplifier circuit is realized with the power amplifier IC
–LA78040.
T
he TDA8177 is a 7 pins vertical deflection circuit (2 Amperes) for DC-coupled 90° or 110°
deflection systems with frame frequencies from 50 up to 120 Hz. Only a single supply voltage for the
scan and a second supply for the flyback are needed.
T
he vertical drive currents of N301 pins 21 and 22 are connected to input pins 1 and 7 of the
TDA8177. The currents are converted into a voltage by resistor R405. Pin 2 is on a fixed DC level
(internal bias voltage, about 2.3V) and on pin 1 the drive voltage can be measured (typical 1.4 Vpp).
5
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