Nad T 512 AH Service Manual

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CONTENTS SECTION 1 . . . . SUMMARY SECTION 2 . . . . CABINET & MAIN CHASSIS SECTION 3 . . . . ELECTRICAL SECTION 4 . . . . MECHANISM SECTION 5 . . . . REPLACEMENT PART LIST

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SECTION 1SUMMARY CONTENTS PRODUCT SAFETY SERVICING GUIDELINES FOR VIDEO PRODUCTS ........................... 1-3 SERVICING PRECAUTIONS ........................................................................\ .......................... 1-4 - General Servicing Precautions - Insulation Checking Prodedure - Electrostatically Sensitive Devices SPECIFICATIONS ........................................................................\ .............................................. 1-5

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3-1 SECTION 3 ELECTRICAL CONTENTS ELECTRICAL TROUBLESHOOTING GUIDE ......................................................................3-\ 2 1. Power(SMPS) Circuit ........................................................................\ .................................. .....3-2 2. µ-com Circuit........................................................................\ ........................................ ............3-3 3. MPEG Circuit........................................................................\ ......................................... ...........3-6 4. Front Circuit(Digitron & Key) ........................................................................\ ....................... .3-7 5. RF/Servo Circuit ........................................................................\ ..................................... .........3-8 BLOCK DIAGRAMS ........................................................................\ ..........................................3-12 1. Overall Block Diagram ........................................................................\ ................................ ..3-13 2. Power (SMPS) Block Diagram ........................................................................\ ......................3-14 3. RF/CD DSP/DVD DSP/DVD servo Block Diagram ..............................................................3-14 4. Audio Block Diagram ........................................................................\ .................................. ..3-15 5. MPEG & MEMORY Block Diagram ........................................................................\ ...............3-16 CIRCUIT DIAGRAMS ........................................................................\ ........................................3-17 1. Power (SMPS) Circuit Diagram ........................................................................\ ....................3-17 2. DVD DSP Circuit Diagram ........................................................................\ .............................3 -19 3. Drive & RF Circuit Diagram ........................................................................\ .......................... 3-21 4. MPEG Circuit Diagram ........................................................................\ ................................ ..3-23 - WAVEFORMS ........................................................................\ ............................................. ......3-25 5. Audio Circuit Diagram ........................................................................\ ............................... ....3-27 6. MEMORY Circuit Diagram ........................................................................\ .............................3- 29 7. FRONT Circuit Diagram........................................................................\ ............................... ..3-31 8. A/V JACK Circuit Diagram ........................................................................\ ............................ 3-33 - CIRCUIT VOLTAGE CHART ........................................................................\ ............................3-35 PRINTED CIRCUIT DIAGRAMS ........................................................................\ ....................3-39 1. MAIN P.C.BOARD ........................................................................\ ...................................... .....3-39 2. POWER,A/V,FRONT P.C.BOARD ........................................................................\ ..................3-41 3. KEY P.C.BOARD........................................................................\ ......................................... ....3-43

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3-7 NO NO NO START Does remote controlwork normally? Do all the buttons work normally? Check waveform of IC901 Pin 14. Check waveform of IC901 Pin 18, 19. Is Digitron on normally? LED ON? Check waveform of IC901 Pin 7. Is oscillation ofX901 normal? Is waveform of IC901 Pin 21 normal? Check waveformof IC901 Pin 14. Does pulse waveform of RC901 Pin 1 appear? Is IC901 Pin 17 connected to RC901 Pin 1 ? Is RC901 Pin 2 5V? Power on. Check and replace R903,R912, R904, R905, R941, R906, R907. Solder defective parts again. Solder defective parts Replace IC901. Solder Key part. Check Power. Replace IC902. Replace IC901. Replace LED913. Replace RC901. Re-solder. Recheck Replace IC901. Complete repairing Front B/D. NO NO NO NO NO NO NO NO NO YES YES YES YES YES YES YES YES YES YES YES YES YES YES YES YES CD 4. Front Circuit (Digitron & key)

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3-19 3-20 TRACKING LOOP FOCUS LOOP SLED LOOP SPINDLE LOOP WAVEFORM 5 6 5 2. DVD DSP CIRCUIT DIAGRAM

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3-23 3-24 4. MPEG CIRCUIT DIAGRAM Optical/Coaxial out CVBS Y/Pb/Pr(Componet) Y/C(S-VHS) WAVEFORM