Sharp GXCH-170-X, GXCH-170-Z Service manual

Illustration: GX-CH170Z

GX-CH170X/CH170Z

SERVICE MANUAL

No. S6631GXCH170Z

GX-CH170X GX-CH170Z

• In the interests of user-safety the set should be restored to its original condition and only parts identical to those specified should be used.

CONTENTS

Page

SPECIFICATIONS ............................................................................................................................................................. 2

VOLTAGE SELECTION (GX-CH170Z ONLY)................................................................................................................... 2

NAMES OF PARTS ........................................................................................................................................................... 3

REMOTE CONTROL ......................................................................................................................................................... 4

DISASSEMBLY.................................................................................................................................................................. 5

REMOVING AND REINSTALLING THE MAIN PARTS..................................................................................................... 7

FITTING OF DIAL POINTER ............................................................................................................................................. 8

ADJUSTMENT ................................................................................................................................................................... 9

TROUBLESHOOTING (CHANGER/CD SECTION) ........................................................................................................ 11

NOTES ON SCHEMATIC DIAGRAM .............................................................................................................................. 16

TYPES OF TRANSISTOR AND LED............................................................................................................................... 16

BLOCK DIAGRAM ........................................................................................................................................................... 17

SCHEMATIC DIAGRAM / WIRING SIDE OF P.W.BOARD............................................................................................. 20

WAVEFORMS OF CD CIRCUIT...................................................................................................................................... 35

FUNCTION TABLE OF IC................................................................................................................................................ 36

LCD SEGMENT ............................................................................................................................................................... 37

PARTS GUIDE/EXPLODED VIEW

DIFFERENCE BETWEEN GX-CH170X AND GX-CH170Z

GX-CH170X

TUNER 2 BAND 4 BAND FINE TUNING FM STEREO INDICATOR POWER SOURCE AC 220-240 V,50 Hz AC 110-127/220-240 V,

GX-CH170Z

50/60 Hz

SHARP CORPORATION

GX-CH170X/CH170Z

FOR A COMPLETE DESCRIPTION OF THE OPERATION OF THIS UNIT, PLEASE REFER TO THE OPERATION MANUAL.

SPECIFICATIONS

General

Power source: AC 220-240 V, 50 Hz (GX-CH170X) DC 12 V [ "D" size (UM/SUM-1,

R20 or HP-2) battery x 8]

Power source: AC 110-127/220-240 V, 50/60 Hz (GX-CH170Z) DC 12 V [ "D" size (UM/SUM-1,

R20 or HP-2) battery x 8]

Power consumption: 55 W Output power: PMPO; 60 W (total)

MPO (Max.); 24 W (12 W + 12 W) (AC operation) RMS; 10 W (5 W + 5 W) (DC operation, 10 % T.H.D.)

Output terminal: Headphones; 16 - 50 ohms

(recommended; 32 ohms)

Dimensions: Width; 290 mm (11-1/2")

Height; 260 mm (10-1/4") Depth; 277 mm (10-15/16")

Weight: 4.3 kg (9.5 Ibs.) without batteries

Compact disc player

Type: Twin CD mechanism Signal readout: Non-contact, 3-beam semi-

conductor laser pickup

Audio channels: 2 D/A converter: 1-bit D/A converter Decoder: 16-bit linear quantization Filter: 4-tims oversampling digital filter Wow and flutter: Unmeasurable

(less than 0.001% W. peak)

Radio

Frequency range: FM; 87.6 - 108 MHz (GX-CH170X) AM; 530 - 1,702 kHz Frequency range: FM; 88 - 108 MHz (GX-CH170Z) MW; 526.5 - 1,606.5 kHz

SW1; 2.3 - 7.3 MHz SW2; 7.3 - 22 MHz

Tape recorder

Frequency response: 50 - 14,000 Hz (Normal tape) Signal/noise ratio: 50 dB (TAPE 1, recording /

playback)

55 dB (TAPE 2, playback)

Wow and flitter: 0.25 % (WRMS) Motor: DC 12 V electric governor Bias system: AC bias Erase system: AC erase

Speaker section

Type: 2-way 4-speaker bass-reflex type Speakers: 10 cm (4") woofer x 2

Tweeter x 2

Maximum input power: 8 W Impedance: 3.2 ohms Dimensions: Width; 190 mm (7-1/2")

Height; 260 mm (10-1/4") Depth; 183 mm (7-1/4")

Weight: 1.3 kg (2.9 Ibs.) /each

Specifications for this model are subject to change without prior notice.

VOLTAGE SELECTION (GX-CH170Z ONLY)

Before operating the unit on mains, check the preset voltage. If the voltage is different from your local voltage. Slide the AC power supply socket cover by slightly loosing the screw to the visible indication of the side of your local voltage.

92LCoRD577BQACCB0004AW00

QACCE0007AW00 92LPLUG027 92LPLUG155A

Figure 2 AC POWER SUPPLY CORD AND AC PLUG ADAPTOR

– 2 –

NAMES OF PARTS

Main unit (Illustration: GX-CH170Z)

1. Disc Number Indicator

2. Random Indicator

3. CD Play Indicator:

4. Track Number/Minutes and Seconds/Volume Level/ Programme Number Indicator

5. Programme Indicator

6. CD Repeat Indicator:

7. (DISC 1) Open/Close Button:

8. (DISC 1) Indicator

9. (DISC 1) Disc Tray

10. Random Play Button

11. Clear Button

12. Programme Button

13. (DISC 2) Indicator

14. (DISC 2) Open/Close Button:

15. (DISC 2) Disc Tray

16. DISC 1 2 Select Button

17. (CD) Play/Repeat Button:

18. (CD) Stop Button:

19. (CD) Pause Button:

20. (CD) Track Up/Cue Button:

21. (CD) Track Down/Review Button:

22. Remote Control Sensor

23. Extra Bass Control: X-BASS

24. Graphic Equalizer Controls

25. Stand-By Indicator

26. Tuning Control

27. Power Button

28. Volume Up/Down Button:

29. FM Stereo Indicator (GX-CH170Z ONLY)

30. Dubbing Speed/Beat Cancel Switch

31. Band Selector Switch (GX-CH170X)

31. Tape Selector/FM Mode Switch (GX-CH170Z)

32. Function Selector/Remote Control Switch

33. Band Selector Switch (GX-CH170Z ONLY)

34. Fine Tuning Control (GX-CH170Z ONLY)

35. (TAPE 1) Cassette Compartment

36. (TAPE 1) Record Button:

37. (TAPE 1) Play Button:

38. (TAPE 1) Rewind Button:

39. (TAPE 1) Fast Forward Button:

40. (TAPE 1) Stop/Eject Button:

41. (TAPE 2) Play Button:

42. (TAPE 2) Stop/Eject Button: /

43. (TAPE2) Cassette Compartment

1 2

GX-CH170X/CH170Z

1 2

RANDOM

VOLUME

PROGRAM

1011 12 13

22 2120 1918 17

24 25 26 27

31 32 33 34

383736 3940 41 4235 43

28 29

Rear panel

44. FM Telescopic Rod Aerial (GX-CH170X)

44. FM/SW Telescopic Rod Aerial (GX-CH170Z)

45. Headphone Socket

46. Speaker Terminals

47. Battery Compartment

48. AC Power Input Socket

49. AC Voltage Selector (GX-CH170Z ONLY)

– 3 –

GX-CH170X/CH170Z

Speaker section

1. Tweeter

2. Woofer

3. Bass Reflex Port

4. Speaker Wire

1 2

Remote Control

5. Remote Control Transmitter LED

6. Power Button

7. Track Down/Review Button:

8. Pause Button:

9. Random Button

10. Play/Repeat Button:

11. DISC 1 2 Select Button

12. Track Up/Cue Button:

13. Stop Button:

14. Programme Button

15. Volume Up/Down Buttons:

(Illustration: GX-CH170X)

0.3 m - 6 m (12" - 20')

25˚

REMOTE CONTROL

Notes concerning use:

Replace the batteries if control distance decreases or operation becomes erratic.

Periodically clean the transmitter LED on the remote control and the sensor on the main unit with a soft cloth.

25˚

Exposing the sensor on the main unit to strong light may interfere with operation. Change the lighting or the direction of the unit.

Keep the remote control away from moisture, excessive heat, shock, and vibrations.

6 7

8 9

11 12

13 14

– 4 –

DISASSEMBLY

Caution on Disassembly

Follow the below-mentioned notes when disassembling the unit and reassembling it, to keep it safe and ensure excellent performance:

1. Take cassette tape and compact disc out of the unit.

2. Be sure to remove the power supply plug from the wall outlet before starting to disassemble the unit.

3. Take off nylon bands or wire holders where they need be removed when disassembling the unit. After servicing the unit, be sure to rearrange the leads where they were before disassembling.

4. Take suffcient care on static electricity of integrated circuits and other circuits when servicing.

STEP REMOVAL PROCEDURE FIGURE

UNIT

1 Front Cabinet 1. Screw.................. (A1) x11 5-1

2. Socket...................(A2) x1 5-2

3. Tip.........................(A3) x1 6-5

2 CD Block 1. Screw....................(B1) x2 5-2

2. Socket...................(B2) x3 5-3

3 Graphic EQ. PWB 1. Screw ................... (C1) x3 5-3

2. Socket.................. (C2) x1

4 Tuner PWB 1. Screw ................... (D1) x2 5-3

(with Tuner Frame) 2. Flat Cable .............(D2) x1

5 Main PWB 1. Hook .....................(E1) x1 5-3

2. Flat Cable............. (E2) x3 5-3,6-1

6 Display PWB/ 1. Screw .................... (F1) x9 5-3,6-1

Switch PWB 2. Hook ..................... (F2) x1 6-1

7 Deck PWB 1. Screw................... (G1) x3 6-1

2. Socket.................. (G2) x3

8 Tape Mechanism 1. Open the cassette holder.

2. Screw................... (H1) x6 6-2

9 CD Servo PWB 1. Screw.................... (J1) x2 6-3

10 CD Mechanism 1. Screw....................(K1) x6 6-4

11 Power PWB/ 1. Open the battery lid.

Terminal PWB 2. Screw .................... (L1) x4 6-5

3. Hook ..................... (L2) x1

SPEAKER

1 Front Panel 1. Screw .................. (N1) x4 6-6

( A1 ) x2 ø3 x6mm

( B1 ) x1 ø3 x10mm

Front Cabinet

Switch PWB

Rear Cabinet

Front Cabinet

Figure 5-1

Figure 5-2

( E1 ) x1

GX-CH170X/CH170Z

( A1 ) x2 ø3 x6mm

( A1 ) x2 ø3 x10mm

( A1 ) x4 ø3 x20mm

( A1 ) x1 ø3 x65mm

( B1 ) x1 ø3 x10mm

CD Block

Main PWB

( A2 ) x1

Switch

( F1 ) x2

PWB

ø3 x10mm

Graphic EQ. PWB

( C1 ) x3 ø3 x10mm

Main PWB

( F1 ) x2 ø3 x10mm

( D1 ) x1 ø3 x10mm

– 5 –

( D2 ) x1

( B2 ) x3

Tuner PWB

Figure 5-3

( D1 ) x1 ø3 x10mm

( C2 ) x1

( E2 ) x1

GX-CH170X/CH170Z

Front Cabinet

Display PWB

( F2 ) x1

( F1 ) x5 ø3 x10mm

( G1 ) x3 ø3 x10mm

( G2 ) x2

( K1 ) x2 ø2.6 x8mm

( K1 ) x3 ø2.6 x10mm

( K1 ) x1 ø2.6 x8mm

Tape Mechanism

Front Cabinet

Tape Mechanism

Deck PWB

Figure 6-1

Figure 6-2

( G2 ) x1

( E2 ) x2

( H1 ) x6 ø3 x10mm

Rear Cabinet

Power PWB

Figure 6-4

Washer

( L1 ) x3 ø3 x10mm

Figure 6-5

CD Mechanism

CD Block

( A3 ) x1

Terminal PWB

( L2 ) x1

Push

Driver ( L1 ) x1 ø3 x10mm

( J1 ) x2 ø3 x10mm

Figure 6-3

CD Servo PWB

CD Block

Front Panel

( N1 ) x4 ø3 x20mm

Figure 6-6

– 6 –

REMOVING AND REINSTALLING THE MAIN PARTS

Pinch Roller (D1) x 1

Pawl

TAPE1 Main Belt (E1)x1

TAPE2 Main Belt (F1)x1

Main Belt (F1)x1

Main Belt (E1)x1

FF/REW Belt (E2)x1

Flywheel

Motor

TAPE 1

TAPE 2

TAPE MECHANISM SECTION

Perform steps 1, 2, 3, 4, 5, 7 and 8 of the disassembly method to remove the tape mechanism.

How to remove the record/playback and erase heads (TAPE 1) (See Fig. 7-1.)

1. Carefully bend the record/playback head pawls (A1) x 2 pcs., in the direction of the arrow , and remove the record/ playback head upwards.

2. Remove the screws (B1) x 2 pcs., to remove the erase head.

How to remove the playback head (TAPE 2) (See Fig. 7-2.)

1. Carefully bend the playback head pawls (C1) x 2 pcs., in the direction of the arrow , and remove the playback head

upwards.

How to remove the pinch roller (TAPE 1/2) (See Fig. 7-3.)

1. Carefully bend the pinch roller pawl in the direction of the arrow , and remove the pinch roller (D1) upwards.

How to remove the belt (TAPE 1) (See Fig. 7-4.)

1. Remove the main belt (E1) x 1 pc., from the motor side.

2. Remove the FF/REW belt (E2) x 1 pc.

How to remove the belt (TAPE 2) (See Fig. 7-4.)

1. Remove the tape 2 main belt (E1) x 1pc., from the motor side.

2. Remove the tape 1 main belt (F1) x 1pc., from the motor side.

How to remove the motor (See Figs. 7-5 and 7-6.)

1. Remove the belt.

2. Remove the screws (G1) x 4 pcs., to remove the motor

fixtire.

3. Remove the screws (G2) x 2 pcs., to remove the motor.

Note:

When mounting the motor, pay attention to the motor mounting angle.

TAPE2 TAPE1

( G1 ) x2 ø2 x4mm

( B1 ) x2 ø2 x7mm

Erase Head

Play Button

TAPE 1

Figure 7-1

TAPE 2

Figure 7-2

GX-CH170X/CH170Z

Record/Playback Head

Pawl (A1)x2

Playback Head

Pawl (C1)x2

( G2 ) x2 ø2.6 x2mm

Motor

Motor Bracket

Motor

Figure 7-5

Figure 7-6

Figure 7-3

( G1 ) x2 ø2 x4mm

Motor Bracket

Figure 7-4

– 7 –

GX-CH170X/CH170Z CD MECHANISM SECTION

Perform steps 1, 2, 9 and 10 of the disassembly method to remove the CD mechanism.

(A1) x2

2.6 x6mm

How to remove the pickup (See Fig. 8-1.)

1. Remove the screws (A1) x2 pcs., to remove the shaft (A2) x 1 pc.

2. Remove the stop washer (A3) x1 pc., to remove the gear (A4) x 1 pc.

3. Remove the pickup.

Pickup

CD Mechanism

Stop Washer (A3) x1

Gear

Shaft

(A4) x1

(A2) x1

Figure 8-1

FITTING OF DIAL POINTER

1. Remove the three screws, and remove the tuner PWB from the tuner frame. (See Fig. 8-2) [GX-CH170X]

1. Remove the four screws, and remove the tuner PWB from the tuner frame. (See Fig. 8-2) [GX-CH170Z]

2. Turn fully the dial wheel in the direction. (See Fig. 8-3)

3. Set the dial pointer as shown in Figure 9-2, and mount the tuner PWB.

(GX-CH170X)

"0" Point

Tuner Frame

(GX-CH170Z)

"0" Point

Dial Pointer ( 235 )

Tuner PWB

(Top view)

Screw x3

Screw x4

Tuner PWB

(Bottom view)

Tuner PWB

(Bottom view)

Tuner PWB

(Top view)

Figure 8-2 Figure 8-3

– 8 –

MECHANISM SECTION

• Driving Force Check

Torque Meter

PLAY: TW-2412 Tape 1: Over 50 g

Tape 2: Over 100 g

• Torque Check

Torque Meter

Play: TW-2111 30 to 60 g.cm 30 to 60 g.cm Fast Forward: TW-2231 80 to 135 g.cm Rewind: TW-2231 80 to 135 g.cm

• Tape Speed

Test Tape

Nomal MTT-111 VR391 3,000 Speaker speed ± 30 Hz terminal

Adjusting

Parts

TAPE SECTION

Position of each switch or control

Volume control Max Beat cancel A Function/Power switch Tape/Off

• Bias Oscillation Check

Beat cancel A: 82 + 10 kHz / -6 kHz

• Erase Current Check

Resistor for measurement: 1 ohm 50 ± 15 mV

• Playback Amplifier Sensitivity Check

Test Tape Specified Value

MTT-118 1.8 V ± 3 dB Speaker Terminal

Pin 13 of IC2 Pin 21 of IC2

FET : 2SK19 or 2SK54

10 kohm

Figure 9-1 VCO FREQUENCY TEST CIRCUIT

(GX-CH170X)

Specified Value

Tape 1

Specified

Value

Tape 2

Instrument

Connection

(Load resistance: 6 ohms)

Specified Value

B: -2 ± 2 kHz -4 -9 C: +3 ± 2 kHz 0 +1.5

Specified Value

Instrument Connection

(Load resistance: 6 ohms)

TO FREQUENCY COUNTER

ADJUSTMENT

TUNER SECTION

fL: Low-range frequency fH: High-range frequency

• FM IF/RF

Test Stage

IF T1 Detection T2 Band Coverage 87.4 MHz (fL): L2

Tracking 88.0 MHz (fL): L1

• AM IF/RF

Test Stage

IF T3

AM Band Coverage fL: L4 (510 kHz) (GX-CH170X) fH: TC4 (1,750 kHz)

MWBand Coverage fL: L5 (510 kHz) (GX-CH170Z) fH: TC6 (1,650 kHz)

SW1 Band Coverage fL: L4 (2.25 MHz) (GX-CH170Z) fH:TC4 (7.4 MHz)

SW2 Band Coverage fL: L7 (7.2 MHz)

(GX-CH170Z) fH: TC8 (22.5 MHz) AM Tracking 600 kHz: L3

(GX-CH170X) 1,400 kHz: TC3 MW Tracking 600 kHz: L3 (MW)

(GX-CH170Z) 1,400 kHz: TC5 SW1 Tracking 2.6 MHz: L3 (SW1)

(GX-CH170Z) 6.0 MHz: TC3 SW2 Tracking 8.5 MHz: L6

(GX-CH170Z) 19 MHz: TC7

• VCO Frequency

Adjusting Point

VR1 76 kHz ± 200 Hz Pin 13, pin 21 and

Note:

After preparing the test circuit shown in Fig. 9-1, connect the Pin 13, Pin 21 and ground of the IC2 with the test circuit, and measure the value. At this time, apply a standard unmodulated signal input and adjust the VCO.

(GX-CH170Z)

GX-CH170X/CH170Z

Specified

Value/Adjusting Point

108.2 MHz (fH): TC2

108.0 MHz (fH): TC1

Specified

Value/Adjusting Point

Specified

Value

Instrument

Connection

Input: Pin 1 of IC1 Output: Pin 17 of IC2

Iuput: Antenna Output: Headphones Socket (Load resistance: 32 ohms)

Instrument

Connection

Input: Antenna Output: Pin 19 of IC2

Input: Antenna Output: Headphones Socket (Load resistance: 32 ohms)

Instrument

Connection

ground of IC2

FM TRACKING

fH fL

AM BAR ANTENNA

AM TRACKING fL

AM TRACKING fH

TC3

TC1

FM RF 1

IC1

FM IF

TC4

TC2

FM DET

AM IF

IC2

TC3

TC4

VR1

VCO

SW1 TRACKING fLMW TRACKING fL

SW1 TRACKING fH MW TRACKING fH

TC5

TC7

TC8

TC6

fH SW2 fL TRACKING

fH SW1 BAND fL COVERAGE

fL MW BAND fH COVERAGE

fL SW2 BAND fH COVERAGE

AM BANDfH

COVERAGE

VCO

VR1

FM BANDfL

COVERAGE

FM fL TRACKING fH

FM BAND fH

COVERAGE fL

IC1

FM IF

AM IF

MW/SW1 BAR ANTENNA

TC1

TC2

21 19 17

FM DET

IC2

Figure 9-2 ADJUSTMENT POINTS

– 9 –

GX-CH170X/CH170Z

CD SECTION

Since this CD system incorporates the following automatic adjustment function, when the pickup is replaced, it is necessary to reajust it. Since this CD unit does not need adjustment, the combination of PWB and laser pickup unit is not restricted.

TEST MODE

Start

Note

Operation

After setting the FUNCTION switch to "CD" turn on power. Not later than 1s but later than 500 msec after power is turned on press simultaneously the following buttons.

1. CD TEST mode DISC1/2 + DOWN/REVIEW

2. LCD TEST mode DISC1/2 + UP/CUE

3. ELECTRONIC VOLUME TEST mode DISC1/2 + STOP

1. When the CD LID switch is in the OFF position, the unit will be able to enter the test mode. However, playback cannot be performed in this mode.

2. The LCD lights wholly. The use of the "UP/CUE" button will move the pickup to the outermost position.

The use of the "DOWN/REVIEW" button will move the pickup to the innermost position. When the "PLAY" button is pressed, the laser will be lit, and when the "STOP" button is pressed, it will be

turned off. Playback will also start and stop when these buttons are pressed. a. If the "PLAY" button is pressed while in the stop mode, the laser will simply be turned on at first.

b. If the laser is lit and the "PLAY" button is pressed again, playback will start from the current pickup position. c. If the "STOP" button is pressed, playback will stop. When pressed again, the laser will be turned off.

Turning the tracking servo on or off.3 a. Each time the PAUSE button is pressed during playback, the tracking servo will be turned on or off.

(Note: If the PLAY button is pressed while in the stop mode, the tracking servo will automatically be turned on.)

When the TEST mode is entered, at first the CD mechanism is shifted to Tray 1 or Tray 2. The CD mechanism can be shifted by using the DISC1/2 button. TRAY-1 OPEN/CLOSE button: The Tray1 can be opened and closed. TRAY-2 OPEN/CLOSE button: The Tray2 can be opened and closed.

LCD MODE

Display

* After the number 3 has appeared in the display, each time the "UP/CUE" button is pressed, the display will switch

in the following order: 1, 2, and then 3.

ELECTRONIC VOLUME TEST MODE

Operation

VOL is set to -14 dB (LCD indication "5"). The VOL setting is changed as follows by using the "VOL UP" button or "VOL DOWN" button.

VOL UP button: VOL setting Min VOL setting -14 dB VOL setting Max

LCD indication "0" LCD indication "5" LCD indication "10"

VOL DOWN button: VOL setting Max VOL setting -14 dB VOL setting Min

LCD indication "10" LCD indication "5" LCD indication "0"

1 second1 second

‘

– 10 –

GX-CH170X/CH170Z

TROUBLESHOOTING (CHANGER CONTROL SECTION)

When the changer mechanism fails to operate normally.

Operation failure may be caused by blocking of disc at the changer mechanism tray. Therefore, it is necessary to check at first to see whether there is any disc blocking. If no abnormal phenomena were found and the normal operation cannot be resumed, check as follows.

Set the FUNCTION switch to REMOTE ON mode, and set the POWER button to ON.

Set the FUNCTION switch to CD.

Does LCD give an indication?

Yes

Is the tray opened when the OPEN/CLOSE button is pressed?

Yes

Does the CD mechanism move up and stop when disc is selected?

Yes

Is "Er" displayed after normal stop?

Normal

• CD microcomputer operation failure.

Is +5V applied to the pin 7 of FW751?

Yes

Is +5V applied to the pin 25 (VDD) of IC901?

Yes

Is the oscillation circuit (periphery of XL701) of IC901 normal?

Yes

Does LCD display appears when the pin 21 (RESET) of IC901 is instantaneously connected to GND

Check as stated in item "CD MICROCOMPUTER OPERATION FAILURE".

Check as stated in item "THE DISC TRAY CANNOT BE OPENED AND CLOSED".

Check as stated in item "DISC CHANGE FAILURE".

Check the optical pickup IN switch. (SW702)

Yes

Check for contact failure of Flexible wire. If OK, check the main PWB side power

line.

Check the pattern between FW751 and the pin 25 of IC901.

XL701 or IC901 is faulty.

Check the reset line.

Yes

Does the LCD indication change in the LCD TEST mode?

Yes

Normal

Check voltage on the pins 41, 42, 43, and 44 of IC901. If OK, IC951 or LCD801 is

faulty.

– 11 –

GX-CH170X/CH170Z

• The disc tray cannot be opened and closed.

Is +7.4V applied to the pin 6 of IC761?

Yes

Does the LCD "?" indication rotate when the main unit or remote control OPEN/CLOSE button is pressed?

Yes

Check that the pin 64 of IC901 is in Low state but the pin 1 is in High state when the OPEN/CLOSE button is pressed. (Tray 1 unloading) (Tray 2 unloading: Pin 64 High, pin 1 Low)

Yes

Check that +6V is output to the pin 9 in Tray1 mode and that +6V is output to the pin 7 in Tray2 mode.

Yes

Is about +6V output between pins 4 and 5 of CNP753?

Yes

Is about +6V applied to the loading motor M981C?

Yes

Check the loading motor M981C and loading mechanism.

Check the +7.5V power line.

Check the main unit button or remote control.

Check IC901.

IC761 is defective.

Check the pattern between IC761 and CNP753.

Check for breakage of connecting wire for loading motor M981C.

IC901 IC761

Pin 1 Pin64 Pin 7

Tray1 Open H L 0 +6V Reverse Tray2 Open L H +6V 0 Forward Tray1 Close L H +6V 0 Forward Tray2 Close H L 0 +6V Reverse

Pin 9

M981C

Motor

operation

• Disc change failure.

Is +7.4V applied to the pin 6 of IC761?

Does the LCD "?" indication rotate when the main unit or remote control DISC CHANGE button is pressed?

Yes

Disc move failure?

Operation failure

Check that the IC901 pin voltage is as follows:

Pin 1 Pin 64

Disc2 -> Disc1 L H Disc1 -> Disc2 H L

Yes

Remains persistently.

Check the main unit button or remote control.

Check the changer mechanism switches.

IC901 is defective.

Check that the IC761 pin voltage is as follows:

Pin 7 Pin 9

Disc1 -> Disc2 0 +6V Disc2 -> Disc1 +6V 0

Yes

Is voltage applied to the loading motor M781C?

Yes

The motor M981C is defective.

IC761 is defective. Or check the pattern between pin 64 of IC901 and

pin 1 of IC761, the pattern between pin 1 of IC901 and pin 3 of IC761.

Check for breakage of wire CNW753 to loading motor M981C.

– 12 –

GX-CH170X/CH170Z

TROUBLESHOOTING (CD SECTION)

When the CD does not function

When the CD section does not operate When the objective lens of the optical pickup is dirty,this section may not operate.Clean the objective lens,and check the playback operation.When this section does not operate even after the above step is taken,check the following items. Remove the cabinet and follow the troubleshooting instructions. "Track skipping and/or no TOC(Table Of Contents) may be caused by build up of dust other foreign matter on the laser pickup lens. Before attempting any adjustment make certain that the lens is clean. If not, clean it as mentioned below."

Turn the power off. Gently clean the lens with a lens cleaning tissue and a small amount of isopropyl alcohol. Do not touch the lens with the bare hand.

• The CD function will not work.

The CD operating keys don't work.

Yes

Check the CD, DPS microcomputer (IC701), power supply, 4.0 MHz and 16.93 MHz clock, and reset terminal.

Yes

Check the waveform of SCK, SO (DATA) and SI (COMM).

Yes

See if the pick-up is in the pick-up in SW4 position.

Yes

If the items mentioned above are OK, check the main microcomputer IC901.

• The CD operating keys work.

Check the Focus - HF system.

When the PLAY button is pressed without first loading a disc, does the pickup go up and down?

Yes

Does the pick-up move up and down twice?

Does the output waveform of IC801(16)(FD) match that shown in Fig. 13?

Check the IC801(50)(CLK) line, 4MHz. Check the microcomputer data on pins (51)(CL), (52)(DAT) and (53)CE.

Yes

0.5s

0.50 V IC801 16 FD

0.5s

0.50 V IC801 15 TD

Focus search OK.

Check the area around IC804-BI801/CNS801.

Focus search is performed two times when play operation is done without disc.

– 13 –

1 2

Figure 13

GX-CH170X/CH170Z

• Playback can only be performed when a disc is loaded.

Is the Focus servo active? (Can you hear it working?)

Yes

Does the DRF signal change from "L" to "H"?

Yes

Is HF waveform normal (see the Fig.14-1, 2)?

Yes

Check the tracking system.

0.1V/DIV

0.5µsec/DIV(DC) (When playing back the disc)

0.5s

1.00 V IC801 16 FD

0.5s

10.0 V IC801 12 CLV+

0.5s

10.0 V IC801 54 DRF

0.5s

2.00 V IC801 7 TE

Check the laser diode driver. Check the area around IC801(16) - (21) (focus servo circuit).

Yes If the disc is not turning, the DRF should not change to "H".

Check the spin system.

Yes

Level is abnormal.

Check the periphery of IC801 pins 41 and

42.

Yes Waveform is unstable.

Check the spin system.

Waveform in case of normal playback

2 1

3 4

Figure 14-1

• Check the tracking system.

Check waveform of IC801 pin 7 (TE).

The waveform shown in Fig. 14-3 appears, and no-disc state appears soon.

Play is possible in TEST mode.

Data cannot be read.

Yes

Although IL is possible, play is impossible.

Yes

5ms

1.00 V IC801 7 TE

Yes

Tracking servo is inoperative.

Normal jump is impeded, and the program top cannot be reached.

Yes

Check the VCO-PLL system.

Figure 14-2

Yes

Check the periphery of IC801 pin 8 to pin 15, and IC804 to BI801/CNS801.

Check the periphery of IC801 pin 14.

Yes

5 ms

5.0 V IC801 54 DRF

Figure 14-3

– 14 –

• Checking the spin system.

Play operation is performed without disc.

Yes

GX-CH170X/CH170Z

The turntable rotates a little.

The turntable fails to rotate or rotates at high speed.

• Checking the VCO-PLL system

Play operation is performed when disc exits.

Yes

Although HF waveform is normal, TOC data cannot be read.

Stop --> Play

As VCO freque-

0.5s

1.00 V IC802 3 PDO

0.5s

1.00 V IC801 16 FD

ncy is locked at

4.32 M Hz, voltage of PDO

rises and stabilizes.

Yes

The spin driver circuit is normal.

Check the periphery of IC801 pins 23 to 27, pin 39 and pin 40, IC802 pin 12 and pin 13, IC804 to BI803/CNS803.

Check PDO waveform (Fig. 15).

Error

Check the IC801 pins 43 and 44, IC802 pins 3, 5, 7, 9 and 10.

Figure 15

• Although HF waveform is normal and the time indication is normal, no sound is emitted.

Check IC802 pin 48 (EFLG).

Yes

Check IC802 pins 37and 40.

Abnomal

Check the periphery of IC803 (OPAMP).

Usually, the number of pulses of flawless disc is 100 pulses/ sec or less.

– 15 –

GX-CH170X/CH170Z

NOTES ON SCHEMATIC DIAGRAM

• Resistor: To differentiate the units of resistors, the symbol as K and M are used: the symbol K means 1000 ohm and the symbol M means 1000 kohm and the resistor without any symbol is an ohm resistor. The resistor designated "Fusible" is a fuse type resistor

• Capacitor: To indicate the unit of capacitor, a symbol P is used: this symbol P means micro-micro-farad and the unit of the capacitor without such a symbol is microfarad. As to electrolytic capacitor, the expression “capacitance/withstand voltage” is used. (CH), (TH), (RH), (UJ): Temperature compensation (ML): Mylar type (P.P.): Polypropylene type

• The indicated voltage in each section is the one measured by Digital Multimeter between such a section and the chassis with no signal given.

REF. NO DESCRIPTION POSITION

SW1 BAND [GX-CH170Z ONLY] FM—SW2—SW1

—MW SW4 PICKUP IN ON—OFF SW201 RECODE/PLAYBACK R—P SW251 DUBBING SPEED/BEAT CANCEL NORMAL A—

NORMAL B—

HIGH C/A—B—C SW253 BAND [GX-CH170X] FM—AM SW253 TAPE SELECTOR/FM MODE NORMAL—CrO2/

[GX-CH170Z] FM STEREO—

FM MONO SW601 TAPE 1 MAIN ON—OFF SW602 TAPE 2 MAIN ON—OFF SW603 TAPE1/2 SELECTOR ON—OFF SW651 FUNCTION/REMOTO CONTROL CD—TUNER—

TAPE—OFF/

ON—OFF SW701 POWER ON—OFF

1. Tuner ( ): AM mode Marking except for ( ): FM mode

2. CD ( ): Play mode Marking except for ( ): Stop state

3. Deck section ( ): Record mode Marking except for ( ): Playback mode Display / Control section: ( ): Active state Marking except for ( ): CD Function mode at stop state

• Schematic diagram and Wiring Side of P.W.Board for this model are subject to change for improvement without prior notice.

• Parts marked with “ ” ( ) are important for

maintaining the safety of the set. Be sure to replace these parts with specified ones for maintaining the safety and performance of the set.

REF. NO DESCRIPTION POSITION

SW702 CD-STOP ON—OFF SW703 CD-PLAY ON—OFF SW704 CD-PAUSE ON—OFF SW705 CD-CUE ON—OFF SW706 CD-REVIEW ON—OFF SW707 CD-DISC 1-2 ON—OFF SW708 CD-RANDOM ON—OFF SW709 VOLUME UP ON—OFF SW710 VOLUME DOWN ON—OFF SW711 CD-PROGRAM ON—OFF SW712 CD-CLEAR ON—OFF SW713 CD-TRAY1 OPEN/CLOSE ON—OFF SW714 CD-TRAY2 OPEN/CLOSE ON—OFF SW981 TRAY/MECHANISM UP ON—OFF SW982 TRAY1 1a—1b SW983 TRAY2 2a—2b

FRONT

VIEW

ECB

(S)(G)(D)

(1) (2) (3)

2SC2001 K 2SB561 C 2SB562 C 2SD468 C KRA102 M KRC102 M KTA1266 GR KTC3199 GR

FRONT

VIEW

FRONT VIEW

BCE

2SD2394 F

Figure 16 TYPES OF TRANSISTOR AND LED

3N4PDN32 3N4GDN32

– 16 –

FRONT VIEW

GREEN

3N8PGN33

RED

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