Brief Introduction Of The Regulator Board; Brief Introduction Of The Combi Board - Philips MC-50/22 Service Manual

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COMBI & REGULATOR
TABLE OF CONTENTS
Brief Introduction on Regulator & Combi Boards ................. 12-1
Regulator (Stabilizer) Board layouts .................................... 12-2
Regulator (Stabilizer) Circuit ................................................ 12-3
Combi Board - Chips layout ................................................. 12-4
Combi Board - Component Layout ....................................... 12-5
Combi Circuit - Power Amplifier part .................................... 12-6
Combi Circuit - Source Select & Sound Control part ........... 12-7
Combi Circuit - Headphone Amp. & Sub-woofer out part .... 12-8
Combi Circuit - Connector & Digital out part ........................ 12-9
Electrical parts list ............................................................... 12-10
12-1
BOARDS

Brief introduction of the Regulator Board

The regulator board provides the following:
a) 12V supply: +12V_A and +12V_M derived from the +A supply
b) 5,6V and 5V supply: +5V6 and 5V_VCD derived from the +A/2 supply

Brief introduction of the Combi Board

1. Source selection & Sound control
Audio Processor IC 7550 (TDA7468D) provides the source selection and sound control features via the I2C bus (I2C_CLK
and I2C_DATA lines).
2. Line out
Line out is taken directly from the Audio Processor IC 7550. Muting is done via Transistors 7500, 7501 and 7508.
3. Pre-amplifier
IC7510 (NJM4556AM) provides pre-amplification of the output signals from the Audio Processor IC 7550. Muting of audio
signals to Power Amplifier IC 7200 during Headphone application and Source switching is done via transistors 7514, 7515,
7540 and 7541
4. Headphone and Sub-woofer outputs
The headphone and Sub-woofer output is taken from the pre-amplifier out. Muting of these outputs are done via transistors
7511, 7512, 7522 and 7523.
5. Power Amplifier
IC 7200 (AN7125) is used as Power amplifier. It function as Class G amplifier together with transistor 7204 (BDW94C) which
switches the supply between supply source +A and +A/2.
6. Protection Circuit
Transistors 7201, 7202 and 7203 provides protection against:
- short-circuit of speaker terminals
- short-circuit of speaker terminals to ground
7. Digital out buffer
IC 7525 (74VUD40) act as buffer to boost the digital output level
8. I/O Expander
I/O Expander IC 7526 (M62320FP) converts the I2C bus (I2C_CLK and I2C_DATA lines) into additional control lines.
9. +5V6_CON supply
IC 7529 (MC78L05) provides the necessary supply to power µProcessor IC 7102 (TMP88CU74F) during ECO Power mode.
12-1
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