Hisense HSM515AV User manual

SERVICE MANUAL
HSM515AV
51CM CTV
SEP04 SERVHSM515AV

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Hisense UOC 2004-10-15
21 ¨ & 14 ¨ Color TV Service Manual
Catalogue
1. Technology Specification and Feature…..……………………… Page 1
2. The IC list …………………………………………………… Page 2
3. Signal process……………………………………………………… Page 2
4. The horizontal and vertical circuit………………………………… Page3
5. Power supply……………………………………………………….. Page 3
6. Appendix 1…………………………………………………………..Page 4
7. Appendix 2....………………………………………………………..Page 9
1．Technology Specification and Feature
I
2C Bus Control
Auto Search
Off/On Timer
Rated Voltage: AC 140V-250V 50Hz/60Hz
Sound output: 5 W×2
Screen size Picture tube 54 cm
System: Color Sound
RF PAL B.G
AV NTSC
Channel coverage: VHF Low channel (VL) =48.25 to 147.25 MHz
VHF high channel (VH) =154.25 to 463.25 MHz
UHF channel U) =471.25 to 863.25 MHz
IF 38.9MHz
External input/output Video/Audio(L/R)2 set input
S-Video input
YUV input
Video/Audio(L/R) 1 set output

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2. IC list
Table 1, the main IC and functions
Number Function IC Remark
1 Power supply KA5Q0765RT N611
2 CPU + SIGNAL PROCESSER OM8370/TDA9370 N301
3 Field driver STV9302A N401
4 Sound driver AN7522N N161
5 AV SWITCH TC4052BP N801 (Video)
N121(sound)
6 Memory AT24C08 N702
7 Photo-coupler HS817B N504
8 IR-receiver HS0038A N1503
9 8V Regulator L7808CV N503
10 5V Regulator L7805CV N505
3. Signal process
The TV signal enters into tuner (A201) from cable or antenna. Pin 10 and pin 11 of N301 are
combined to select the band. Pin 4 of N301 outputs PWM tuning signal. The 38.9MHz IF signal is
coupled to V308 (pre-amplify) and then to SAWF (Z301). After processed in the SAWF, the 38.9MHz
signal gets to pin 23 and pin 24 of OM8370. The IF circuit in OM8370 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 OM8370, the sound signal
comes from the pin 44.
The internal CVBS signal needs norm identification then outputs from pin 38 of OM8370, via the
trap circuit (composed of the V351, Z351, Z354,V352 and so on) feeds back to the pin 40 of OM8370.
The RGB signal comes from pin51, Pin52, Pin53 of OM8370, and outputs to the CRT board.
The internal sound signal comes from pin 44 of OM8370 and then input to pin 1 and pin 12 of
HEF4052BP. The sound signals from RF and AV are selected in it. The selected signal is output from
Pin 3 and pin13, then input AN7522N(sound emplifier) or output from AV terminals.

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4. Horizontal and vertical circuit:
Through Synchronous separating circuit, the video signal is divided into horizontal-
Synchronizing signal and Vertical-Synchronizing signal. The horizontal-Sync pulse coming from pin
33 is transferred to the horizontal-drive transistor.
The cathode driving voltage 180V vertical drive voltage +15V and –15V are all generated from
FBT.
The vertical sawtooth waveform is generated on the pin 21 and 22, and then enters the vertical
amplifier STV9302A.
STV9302A 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. one supply voltage for the scanning
and second voltage supply for the flyback are needed.
The vertical drive currents of OM8370 pins 21 and 22 are connected to input pins 1 and 7 of
STV9302A. The vertical scanning output is coming from pin 5 and feed back to pin 1 by R405. The
supply voltage is ±15V at pin 2 and pin 4. C406 is the pump capacitor.
5. Power supply
The IC of KA5Q0765RT is adapted in this chassis; it is the product of Fairchild. It supplies four
DC voltages, one is the +B＝110V, another is Hcc＝26V, the third is 13V (the sound drive voltage),
the fourth is +16V. The +16V can generate the +8V, +5V and +3.3V by the special generators.

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Appendix 1: IC illustration
Fig.1 OM8370 illustration
Pin1: Standby control,“1”is on,“0”is off.
Pin2: SCL.
Pin3: SDA.

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Pin4: Tuning PWM output.
Pin5: Auto AV control SW, connected with the SCART 8th pin. Input. The rising edge or the falling
edge operates.
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
Pin13: SECAM PLL, connected with a capacitance (No use in this type).
Pin14: +8V power source supply.
Pin15: Using a capacitor of 220n in series to GND, This pin decouples the internal digital supply
voltage of the video processor and minimizes the disturbance to the sensitive analogue parts.
Pin16: Phase-2 control loop, this pin requires a capacitor at 2.2nF (C) in series to GND.
Pin17: Phase-1 control loop, the loop filter connected to pin 17 is suitable for various signal conditions
like strong/weak and VCR signal. This is achieved by switching of the loop filter time constant
by changing the Phase-1 output current.
Pin18: GND.
Pin19: Bandgap decoupling, the bandgap circuit provides a very stable and temperature independent
reference voltage. This reference voltage (4.0 V) ensures optimal performance of the analogue
video processor part of the OM8370 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
because the geometry processor is optimised for this current. Furthermore the output current of
vertical 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
pass filter needed for the DC feedback loop.

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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
heater voltage will rise too. When the rising voltage arrive some limit, the V406 works, the
voltage of pin 36 will exceed 3.9V, the OM8370 will stop working.
Pin37: PLL loop filter.
Pin38: CVBS output. Monitor or RF videos can be selected.
Pin39: +8V supply source.
Pin40: CVBS input
Pin42: Y signal input.
Pin43: C signal input.
Pin44: Main audio output, this pin is connected to the TDA9859.
Pin45: RGB signal input blanking.
Pin46, Pin47, Pin48: RGB signal input.
Pin49: ABL. It means beem current limiter input. R410 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: NC.
Pin63: This pin is connected to the HEF4094, Functions expanding.
Pin64: IR signal input.

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Fig.2 HEF4052BP illustration

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Fig. 3 STV9302A illustration
1INVERTING INPUT 5 VER OUTPUT
2Vcc 6 OUTPUTSTAGEVCC
3PUMP UP OUT 7 NON INV.PUT
4GND
Fig. 4 AN7522N illustration