Page 1 of 2
Circuit Description of J711/J700 DVD Player
1. Power Supply
1.1. The AC power switcher U801 (TOP225Y) drive the fly-back mode transformer
T801, it generate all the secondary DC voltage for both DVD loader and main
board. It also provides –20Vdc and +12Vdc for the front panel VFD.
2. MCU & MPEG decoder
2.1. The MCU and MPEG decoder were integrated into the ICS1 (STI5505).
2.2. Firstly, the ICS3 (74HCU04) and XS1 (27Mhz) crystal generate the 27MHz
clock. It provided the 27Mhz reference to the ICS1 pin 118, then the entire
necessary clock signals were generated inside the ICS1.
2.3. Transistor QS1, QS2, QS3 provide the reset signal to both DVD loader and
ICS1.
2.4. DVD data streams are coming from the HX1 connector, after pass through the
buffer ICX1 (74HC244) it goes into ICS1 pin36 to pin39. The entire MPEG
decode process will be done inside the ICS1.
2.5. The Analog composite video is output from ICS1 pin 64.
2.6. The Analog Y/C videos were output from ICS1 pin 62 and pin 63.
2.7. The Analog RGB videos were output from ICS1 pin 55, pin 56 and pin 57.
3. Memory
3.1. The memory system were consist of Flash ROM (ICM1 /ICM2), EDO DRAM
(ICM3) and SDRAM (ICM4 / ICM8).
3.2. At cool boot, the MCU ICS1 will access the Flash ROM that held the entire
firmware inside.
3.3. Then the variables and run time data will saved into the EDO DRAM.
3.4. SDRAM were mostly used to store the MPEG picture and On Screen Display.
4. Video output circuitry
4.1. The Composite video will be amplified by Transistor QV1 and filtered by CV9,
CV10, it will be buffered by QV5, QV10 and QV4, and then goes into RCA jack
and SCART connector.
4.2. QV2 and QV3 will amplify the Y/C signals and then filtered by LV6 and LV8
before it goes to the SVHS connector P2.
4.3. RGB signals will go through the HS6 connector to the SCART PCB. Then they
will be buffered and amplified by QN1, QN2 and QN3.
5. Audio D/A and output circuitry
5.1. ICS1 will provide the PCM clock from pin 43 and pin 45.
5.2. PCM channel 0 data is on pin 44 (Main Left and Main Right)
5.3. PCM channel 1 data is on pin 24 ( Center and Sub-woofer)
5.4. PCM channel 1 data is on pin 21 (Surround Left and Surround Right)
5.5. All those signals were go into ICA1, ICA3, ICA5 for D/A conversion, then the
analog audio signal will be filtered and amplified by ICA2, ICA7, ICA4, ICA8,
ICA6 and ICA10.
5.6. Mute signal is controlled by ICS1 pin199 and drive by QA5, QA2, QA7, QA6,
QA9, QA8, QA11, QA10, QA13, QA12, QA15 and QA14.
