akira 21WHP3/BN, Service Manual

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Model No: 21WHS3-Bn
Version 1.0
GENERAL DESCRIPTION
AKPH02 chassis series are applied in A14P01/A21P01 respectively which uses
mainly Philips’ advanced UOC-ultimate chip TDA935X/6X/8X and I2C-bus
controlled IC. With combination of microcontroller and small signal processor, the
TDA935X/6X/8X series feature high-integration, high-performance-to-price ratio and
high-reliability and advanced functions with fewer external components, which
provide much convenience for manufacturing and technical service.
Table 1 provides A14P01/A21P01 mainly ICs and functions.
THE SURVEY
Table 1, the main IC and functions
Position Type Function Description
N301 TDA9361/TDA9381 Microcontroller and small signal
processor(UOC)
N702 ST24C08-W EEPROM
N701 AN7522N Sound power amplifier
N401 LA78040 Vertical scan output stage circuit
N801 LC4052B/CD4052BE AV1/AV2 Switch
N121 LC4052B/CD4052BE AV1/AV2 Switch
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 amplifier) or output from AV terminals.