Zenith LX-140 Service Manual Download Page 3

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SECTION 1. GENERAL

SERVICING PRECAUTIONS

NOTES REGARDING HANDLING OF THE PICK-UP

1. Notes for transport and storage

1) The pick-up should always be left in its conductive bag until immediately prior to use.
2) The pick-up should never be subjected to external pressure or impact.

2. Repair notes

1) The pick-up incorporates a strong magnet, and so should never be brought close to magnetic materials.
2) The pick-up should always be handled correctly and carefully, taking care to avoid external pressure and

impact. If it is subjected to strong pressure or impact, the result may be an operational malfunction and/or
damage to the printed-circuit board.

3) Each and every pick-up is already individually adjusted to a high degree of precision, and for that reason

the adjustment point and installation screws should absolutely never be touched.

4) Laser beams may damage the eyes!

Absolutely never permit laser beams to enter the eyes!
Also NEVER switch ON the power to the laser output part (lens, etc.) of the pick-up if it is damaged.

5) Cleaning the lens surface

If there is dust on the lens surface, the dust should be cleaned away by using an air bush (such as used
for camera lens). The lens is held by a delicate spring. When cleaning the lens surface, therefore, a cotton
swab should be used, taking care not to distort this.

6) Never attempt to disassemble the pick-up.

Spring by excess pressure. If the lens is extremely dirty, apply isopropyl alcohol to the cotton swab. (Do
not use any other liquid cleaners, because they will damage the lens.) Take care not to use too much of
this alcohol on the swab, and do not allow the alcohol to get inside the pick-up.

Storage in conductive bag

Drop impact

NEVER look directly at the laser beam, and don’t let 
contact fingers or other exposed skin.

Magnet

How to hold the pick-up

Conductive Sheet

Cotton swab

Pressure

Pressure

Summary of Contents for LX-140

Page 1: ...MICRO COMPONENT...

Page 2: ...UBLESHOOTING 2 2 WAVEFORMS OF MAJOR CHECK POINT 2 11 BLOCK DIAGRAM 2 21 SCHEMATIC DIAGRAMS 2 23 WIREING DIAGRAM 2 31 PRINTED CIRCUIT DIAGRAMS 2 32 INTERNAL BLOCK DIAGRAM OF ICs 2 39 SECTION 3 EXPLODED...

Page 3: ...er be touched 4 Laser beams may damage the eyes Absolutely never permit laser beams to enter the eyes Also NEVER switch ON the power to the laser output part lens etc of the pick up if it is damaged 5...

Page 4: ...tive bag do not place the pick up on the bag This is because there is the possibility of damage by static electricity 4 To prevent AC leakage the metal part of the soldering iron should be grounded 5...

Page 5: ...arges sufficient to damage ESD devices 5 Do not use freon propelled chemicals These can generate electrical charges sufficient to damage ESD devices 6 Do not remove a replacement ESD device from its p...

Page 6: ...1 5 SPECIFICATIONS...

Page 7: ...1 6 MEMO...

Page 8: ...chassis ground unless otherwise specified 5 Keep the signal input as low as possible to avoid AGC and AC action TAPE DECK ADJUSTMENT CH1 CH2 Speaker Out Playback Mode Head Test Tape MTT 114 L ch R ch...

Page 9: ...2 2 CD PART TROUBLESHOOTING...

Page 10: ...2 3 OPEN CLOSE NG...

Page 11: ...2 4 READING DISPLAY CHECK ONLY CD DISPLAY...

Page 12: ...2 5 READING OK CHECK NO DISC DISPLAY...

Page 13: ...2 6 READING OK CHECK A NO DISC DISPLAY...

Page 14: ...2 7 READING OK CHECK B NO DISC DISPLAY...

Page 15: ...2 8 READING OK CHECK C NO DISC DISPLAY...

Page 16: ...2 9 READING OK CHECK D NO DISC DISPLAY...

Page 17: ...2 10 READING OK CHECK E NO DISC DISPLAY...

Page 18: ...2 11 WAVEFORMS OF MAKOR CHECK POINT...

Page 19: ...PINDLE DRIVE AND MOTOR WAVEFORM IC503 pin6 1 2 when TOC reading 5 TRACK DRIVE AND MOTOR WAVEFORM TP560 IC503 pin23 during normal play 6 RF TRACKING AND FOCUS ERROR WAVEFORM IC502 pin8 2 1 23 during no...

Page 20: ...2 13 AUDIO PART...

Page 21: ...2 14...

Page 22: ...2 15...

Page 23: ...2 16...

Page 24: ...e the TU101 Check the OSC waveform of TU101 pin8 Refer to IC102 Troubleshooting YES YES YES YES YES NO NO NO IC102 Troubleshooting Check the power input of IC102 pin8 Check the wavefor of IC102 Pin20...

Page 25: ...the IC103 Refer to IC103 Troubleshooting CE Chip Enable DI Data Input from u com DO Data Output to u com CLK Tuner mode clock Check the Clock of CE DI DO CLK Check the operation END YES YES YES YES N...

Page 26: ...the SW201 and HEAD connector Check the output to speaker Check the CN202 Check the CN201 YES YES YES YES NO NO NO REC Check the signal input of IC201 pin4 11 Check the of CN201 pin4 5 Check the oscil...

Page 27: ...2 20 MEMO...

Page 28: ...BLOCK DIAGRAM 2 21 2 22...

Page 29: ...2 23 2 24 SCHEMATIC DIAGRAMS FRONT POWER SCHEMATIC DIAGRAM...

Page 30: ...2 25 2 26 MAIN DECK SCHEMATIC DIAGRAM...

Page 31: ...2 27 2 28 TUNER SCHEMATIC DIAGRAM...

Page 32: ...2 29 2 30 CDP SCHEMATIC DIAGRAM...

Page 33: ...2 31 2 32 WIRING DIAGRAM...

Page 34: ...2 33 2 34 PRINTED CIRCUIT DIAGRAMS FRONT P C BOARD...

Page 35: ...2 35 2 36 MAIN P C BOARD...

Page 36: ...2 37 2 38 CDP P C BOARD...

Page 37: ...2 39 INTERNAL BLOCK DIAGRAM OF ICs IC300 LC87F73C8A 1 Pin Assignment...

Page 38: ...2 40 IC601 TDA7468D 1 BLOCK DIAGRAM...

Page 39: ...2 41 2 PIN CONNECTION...

Page 40: ...2 42 IC301 BU1923 1 BLOCK DIAGRAM...

Page 41: ...2 43 IC102LA1837 1 BLOCK DIAGRAM IC102LA1837 2 Test Circuit Diagram...

Page 42: ...2 44 IC103 LC72131D 1 Pin Assignments...

Page 43: ...2 45 IC201 AN7312 1 BLOCK DIAGRAM IC701 LA4631 1 BLOCK DIAGRAM...

Page 44: ...addresses are multiplexed on the same pins Row address RA0 RA10 column address CA0 CA7 BA Bank Select Address Selects bank to be activated during row address latch time Selects bank for read write dur...

Page 45: ...3 305 280 451 451 451 A46 295 294 293 291 292 290 A00 251 254 253 250 255 256 257 258 A40 266 266 270 252 268 267 269 NOTE Refer to SECTION 5 REPLACEMENT PARTS LIST in order to look for the part numbe...

Page 46: ...4 1 SECTION 4 SPEAKER SECTION MODEL LXS M140 855 854 853 852 851 861 850 850...

Page 47: ...4 2 MEMO...

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