Sony CDP CX235 Service Manual

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Sony Service Company A Division of Sony Electronics Inc ©2000 All Rights Reserved Printed in U.S.A. S is a trademark of Sony Electronics

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Circuit Description and Troubleshooting: Models: CDP-CX235 CDP-CX270 CDP-CX335 CDP-CX400 CDP-CX450 Prepared by: National Training Department Sony Service Company A Division of Sony Electronics Inc. Course presented by _____________________________________ Date ___________________________________________________ Student Name ___________________________________________

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11 Power On Once the CD Changer is plugged into AC, pressing the front panel Power button permits Syscon to enable regulator IC506. IC506 outputs D+5V, +7V, and a reset signal to power the remaining devices on the BD board and turn on 2 LEDs to illuminate the disc door compartment. AC Power Only When the CD changer was plugged into AC, Syscon IC501 received power at pin 37 and was fully functional as marked by the X501 activity at pin\ s 31 and 32. There is even data and clock signals leaving IC501/pins 18, 19 and 58. These signals go to FL Display Driver IC701, but there is no\ instruction to turn on the front panel display while the unit is still O\ FF. PM3394 , FLUKE & PHILIPS ch3 ch2 ch1 CH1 5.00 V= 1 2 3 T IC501 Activity at Power OFF ChannelName CN501/pin 1. FL Data 1 2. FL CLK (Clock) 2 3. FL LT (Latch)4 Time base = 50usec/div Power ON Syscon IC501 receives the power ON command from the front panel push button at pin 44 (LOW). IC501 responds by outputting a HIGH at IC SW pin 65 to enable regulator IC506. IC506 has three outputs: 1. D+5V from pin 2 is used to: - Power the digital ICs on the DB board; and - Turn on the LED at the disc door compartment. This also lets the user know the unit is ON. 2. +7V from pin 9 is used to: - Power the focus/sled/tracking driver IC102; and - Power the coils and motors on the BD board 3. XRST from pin 6 goes HIGH to: - Unmute the analog audio output lines; and - Enable Servo Control IC101 and the focus/sled/tracking driver IC102 on the BD board. Communications IC501 -“ IC701 At power On, the communications activity increases between IC501 and IC701. This is to provide constant update information to the display IC\ 701. , ch3 ch2 ch1 CH1 5 00 V=CH2!5 00 V= 1 2 3 T IC501 Activity at Power ON Channel Name CN501/pin 1. FL Data 1 2. FL CLK (Clock) 2 3. FL LT (Latch)4 Time base = 50usec/div