Sharp QT-CD141, QT-CD161 User Manual

QT-CD161/141

SERVICE MANUAL

No. S5929QTCD161/

QT-CD161(S)

QT-CD141(BK)

• 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.

Illustration: QT-CD161

CONTENTS
	Page
IMPORTANT SERVICE NOTES (FOR U.S.A. ONLY).......................................................................................................	2
SPECIFICATIONS .............................................................................................................................................................	2
NAMES OF PARTS ...........................................................................................................................................................	3
REMOTE CONTROL ..........................................................................................................................................................	3
DISASSEMBLY ..................................................................................................................................................................	4
REMOVING AND REINSTALLING THE MAIN PARTS .....................................................................................................	5
ADJUSTMENT ...................................................................................................................................................................	6
NOTES ON SCHEMATIC DIAGRAM ................................................................................................................................	9
TYPES OF TRANSISTOR .................................................................................................................................................	9
WAVEFORMS OF CD CIRCUIT ......................................................................................................................................	10
BLOCK DIAGRAM ...........................................................................................................................................................	11
SCHEMATIC DIAGRAM / WIRING SIDE OF P.W.BOARD .............................................................................................	14
TROUBLESHOOTING (CD SECTION) ...........................................................................................................................	23
FUNCTION TABLE OF IC................................................................................................................................................	27
PARTS GUIDE/EXPLODED VIEW
PACKING OF THE SET (FOR U.S.A. ONLY)

DIFFERENCE BETWEEN QT-CD161 AND QT-CD141

SECTION

QT-CD161

QT-CD141

REMOTE CONTROL

HEADPHONE SOCKET

SHARP CORPORATION	This document has been published to be used
	for after sales service only.
– 1 –	The contents are subject to change without notice.

QT-CD161/141

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

IMPORTANT SERVICE NOTES (FOR U.S.A. ONLY)

BEFORE RETURNING THE AUDIO PRODUCT

(Fire & Shock Hazard)

Before returning the audio product to the user, perform the following safety checks.

1.Inspect all lead dress to make certain that leads are not pinched or that hardware is not lodged between the chassis and other metal parts in the audio product.

2.Inspect all protective devices such as insulating materials, cabinet, terminal board, adjustment and compartment covers or shields, mechanical insulators etc.

3.To be sure that no shock hazard exists, check for leakage current in the following manner.

*Plug the AC line cord directly into a 120 volt AC outlet.

*Using two clip leads, connect a 1.5k ohm, 10 watt resistor paralleled by a 0.15μF capacitor in series with all exposed metal cabinet parts and a known earth ground, such as conduit or electrical ground connected to earth ground.

*Use a VTVM or VOM with 1000 ohm per volt, or higher, sensitivity to measure the AC voltage drop across the resistor (See diagram).

*Connect the resistor connection to all exposed metal parts having a return path to the chassis (antenna, metal cabinet, screw heads, knobs and control shafts, escutcheon, etc.) and measure the AC voltage drop across the resistor.

VTVM

AC SCALE

1.5k ohms

10W

	0.15 µ F
	TEST PROBE	CONNECT TO
	TO EXPOSED	KNOWN EARTH
	METAL PARTS
		GROUND

All check must be repeated with the AC line cord plug connection reversed.

Any reading of 0.3 volt RMS (this corresponds to 0.2 milliamp. AC.) or more is excessive and indicates a potential shock hazard which must be corrected before returning the audio product to the owner.

SPECIFICATIONS

● General

Power source: AC 120 V, 60 Hz

	DC 12 V [ "D" size (UM/SUM-1,
	R20 or HP-2) battery × 8]
	DC 3 V [ "AA" size (UM/SUM-3,
	R6 or HP-7) battery × 2 for tuner
	memory]
Power	Stand-by; 1.5 W

consumption: Power on; 20 W

Output power: FTC; 2.0 W min. RMS per channel

	into 8 ohms from 150 Hz to 20
	kHz, with no more than 10 % total
	harmonic distortion.
	RMS; 2.3 W/CH
	(DC operation, 10 % T.H.D.)
Speakers:	4" (10 cm) full-range speaker x 2
Output	Headphones; 16-50 ohms
terminals:	(recommended; 32 ohms)
Dimensions:	Width; 18-15/16" (480 mm)
	Height; 6-1/16" (153 mm)
	Depth; 10" (254 mm)
Weight:	7.1 lbs. (3.2 kg) without batteries
● Radio
Frequency	FM; 87.5 - 108 MHz
range:	AM; 530 - 1,720 kHz

● Tape recorder

Frequency
response:	50 - 14,000 Hz (Normal tape)
Signal/noise
ratio:	50 dB
Wow and
flutter:	0.25 % (WRMS)
Motor:	DC 12 V electric governor
Bias system:	AC bias
Erase
system:	Magnet erase
● Compact disc player
Type:	Compact disc
Signal	Non-contact, 3-beam semi-con-
readout:	ductor laser pickup
Audio
channels:	2
Quantization:	16-bit linear quantization
Filter:	4-times oversampling digital filter
D/A
converter:	1-bit D/A converter
Wow and	Unmeasurable
flutter:	(less than 0.001% W. peak)

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

– 2 –

QT-CD161/141

NAMES OF PARTS

1. Cassette Compartment

3 4 5 6 7 8

2.CD Compartment

3.(TAPE) Record Button:

	4.	(TAPE) Play Button:
	5.	(TAPE) Rewind Button:
	6.	(TAPE) Fast Forward Button:
	7.	(TAPE) Stop/Eject Button: /				1
	8.	(TAPE) Pause Button:				2
				9
	9.	Band/Pause:		10		15
	10.	Tuner Memory
	11.	Volume		16
	12.	Power, On/Function Switch
	13.	Extra Bass Button: X-BASS		12
	14.	(CD) Track Down:	/Review Button:			14
	15.	(CD) Track Up:	/Cue Button:	13 11	17
	16.	(TUNER)Tuning:	/(CD) Stop Button:
	17.	(TUNER) Tuning:	/(CD) Play/Repeat Button:

	18	19
18.	FM Telescopic Rod Aerial
19.	Headphone Socket (QT-CD161 Only)
20.	Battery Compartment
21.	AC Power Input Socket

Remote control (QT-CD161 ONLY)

1.(TUNER) Tuning: /(CD) Play/Repeat Button:

2.(CD) Track Down: /Review Button:

3.Band/Pause:

4.(CD) Track Up: /Cue Button:

5.(TUNER)Tuning: /(CD) Stop Button:

20

21

1

2

4

3

5

REMOTE CONTROL (QT-CD161 ONLY)

Notes concerning use:

●Replace the batteries if the operating distance is reduced or if the operation becomes erratic.

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

●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.

Sensor Remote

	15	8" - 20'
		(0.2 m - 6 m)
	15
		0,2 m - 6 m

– 3 –

QT-CD161/141

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 to

be removed when disassembling the unit. After servicing the unit, be sure to rearrange the leads where they were before disassembling.

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

(B2)x1

ø3x10mm
Top Cabinet	(B1)x1

STEP	REMOVAL		PROCEDURE		FIGURE
1	Rear Cabinet	1. Screw .................		(A1) x10	4-1
		2. Socket ..................		(A2) x1	4-2
2	Top Cabinet	1.	Knob .....................	(B1) x1	4-2
	(with CD Mechanism/	2. Screw ...................		(B2) x3
	Tape Mechanism/	3.	Socket ..................	(B3) x1
	Main PWB)
3	Main PWB/	1.	Screw ...................	(C1) x9	4-3,5-1
	Switch PWB/	2. Socket ..................		(C2) x4	4-3,5-1
	Headphones PWB	3.	Soldering ..............	(C3) x3	4-3
	(QT-CD161 Only)
4	Tape Mechanism	1.	Screw ...................	(E1) x4	5-1
5	CD Mechanism	1. Screw ...................		(F1) x3	5-1
6	Terminal PWB	1. Screw ...................		(G1) x5	5-2
		2. Hook .....................		(G2) x1
7	Battery PWB	1.	Hook .....................	(H1) x2	5-3

Front Cabinet

(B2)x2 ø3x10mm

(A2)x1 (B3)x1 Front Cabinet

Main PWB

Figure 4-2

(C1)x6 (C2)x1 ø3x10mm

(C1)x2

ø3x10mm

Switch

PWB

(A1)x1		Headphones
		PWB
(A1)x6 ø3x12mm
		(C3)x3
ø3x20mm		Main PWB
(A1)x3	Rear Cabinet	(C2)x2
		Top Cabinet
ø3x12mm

Figure 4-3

Figure 4-1

– 4 –

QT-CD161/141

	(E1)x4	(G2)x1
	ø3x10mm

				Push
	(F1)x3
	ø2.5x10mm			Driver
Tape				(G1)x2
Mechanism
			Rear Cabinet	ø3x10mm
				(G1)x1
				ø3x10mm
Top Cabinet		(C1)x1
		ø2.5x8mm
CD Mechanism	(C2)x1

Terminal PWB

	Figure 5-1	(G1)x2
		ø3x10mm
		Figure 5-2
		Rear Cabinet

Pull

(H1)x1		(H1)x1
	Battery PWB	Pull

Figure 5-3

REMOVING AND REINSTALLING THE MAIN PARTS

CD MECHANISM SECTION

Perform steps 1, 2, 3 and 5 of the disassembly method to remove the CD mechanism.

How to remove the pickup (See Fig. 5-4.)

1.Remove the screws (A1) x 2 pcs., to remove the shaft (A2) x1 pcs.

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

3.Remove the pickup.

(A1) x2 ø2.6 x6mm

Pickup

CD

Mechanism

Stop

Washer

Shaft (A3) x1

(A2) x1 Gear

(A4) x1

Figure 5-4

– 5 –

QT-CD161/141

ADJUSTMENT

MECHANISM SECTION

• Driving Force Check

Torque Meter	Specified Value
PLAY: TW-2412	Over 120 g

• Torque Check

Torque Meter	Specified Value
Play: TW-2111	25 to 65 g.cm
Fast Forward: TW-2231	60 to 130 g.cm
Rewind: TW-2231	60 to 130 g.cm
• Head Azimuth

Torque Meter	Specified Value
MTT-114	Output: Speaker Terminal
	(CNP201 Load resistance: 8 ohms)

• Tape Speed

Test	Adjusting	Specified	Instrument
Tape	Point	Value	Connection
MTT-111	In motor	3,000 ± 90 Hz	Output: Speaker
			Teaminal
			(CNP201 Load
			resistance: 8 ohms)

TAPE SECTION

Position of each switch or control

Volume control	Max
Function switch	Tape/Power Off
X-BASS	On

• Bias Oscillation

Adjustment Point	Specified Value	Instrument
		Connection
L301	82 kHz ± 6 kHz	Pin 2 of CNP201
	– 6 kHz

• Playback Amplifier Sensitivity Check

Test Tape	Specified Value			Instrument Connection
MTT-118	1.8 V ± 3 dB			Speaker Terminal
				(Load resistance: 8 ohms)
			FM ROD ANTENNA
AM TRACKING			AM BAND
fL	fH		COVERAGE				MAIN PWB
				T2		R26	TP2
							VR1
		TC1	L4	FM DET.
				21	19	17	13
L3		TP1		IC2			VCO
AM BAR
				1
ANTENNA
		R7
		FM IF	L2			T3
	L1
				AM IF
	FM RF	T1
	1	IC1	FM BAND
			COVERAGE

TUNER SECTION

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

• FM RF

Signal generator: 1 kHz, 75 kHz dev., FM modulated

Test Stage	Frequency	Frequency	Setting/	Instrument
		Display	Adjusting	Connection
			Parts
Band	—	87.5 MHz	(fL): L2	*1
Coverage			2.0 ± 0.1 V
RF	90.0 MHz	90.0 MHz	L1	*2
	(10~30 dB)

*1. Input: Antenna,	Output: TP1
*2. Input: Antenna,	Output: Speaker Terminal

• Detection

Signal generator: 10.7 MHz, FM sweep generator

Test	Frequency	Frequency	Setting/	Instrument
Stage		Display	Adjusting	Connection
			Parts
IF	10.7 MHz	98.00 MHz	T1(Turn	Input: Pin 1 of
			the core of	IC1
			T1 fully	Output: TP2
			counter-
			clockwise.

• AM IF/RF

Signal generator: 400 Hz, 30%, AM modulated

Test Stage	Frequency			Frequency	Setting/		Instrument
				Display	Adjusting		Connection
						Parts
IF	450 kHz			1,720 kHz	T3		*1
Band	—			530 kHz	(fL): L4		*3
Coverage					1.4 ± 0.05 V
Tracking	600 kHz			600 kHz	(fL): L3		*2
	1,400 kHz			1,400 kHz	(fH):TC1
*1. Input: Antenna,			Output: Pin19 of IC2
*2. Input: Antenna,			Output: Speaker Terminal
*3. Input: Input is not connected, Output: TP1
• VCO Frequency
Adjusting Point				Specified		Instrument
				Value		Connection
VR1		76 kHz ± 200 Hz				Pin 13, pin 21 and
						ground of IC2

Note:

After preparing the test circuit shown in Fig. 6-1, 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.

Pin 13 of IC2 Pin 21 of IC2
G	D	FET : 2SK19 or 2SK54
	S		TO FREQUENCY
			COUNTER

10 kohm

Figure 6-1 VCO FREQUENCY TEST CIRCUIT

Figure 6-2 ADJUSTMENT POINTS

– 6 –

QT-CD161/141

TURNING ON THE TEST MODE

The types of test mode for this microcomputer and specific test mode turning-on procedure are as follows. Only the unit key is used. The remote control key is not valid. The power must be turned on while two keys are held down.

(1)CD test mode function

The power is turned while the (PRESET ) and STOP (TUNING ) keys are held down.

(2)Tuner test mode function

The power is turned on while the (PRESET ) and PAUSE (BAND) keys are held down.

(3)LCD test mode function

The power is turned on while the (PRESET ) and MEMORY keys are held down.

CD TEST MODE

When the CD test mode is turned on, the CD pickup is moved to the innermost periphery, and the following indication appears. The operation of CD test mode is as follows.

Indication

(1)The CD pickup is moved with the unit UP key and DOWN key. UP key: The pickup is slid to the outer periphery.

DOWN key: The pickup is slid to the inner periphery. However, when it reaches the innermost periphery, it does not move further inward.

(2)When the PLAY key is pressed in stop state, the laser diode turns on if CD lid is closed.

Indication

(3) When the PLAY key is pressed in laser ON state, playback is started from the current position of pickup.

Indication

The current playback track No. and time are indicated.

(4)When the STOP key is pressed during playback, the laser goes out and playback is stopped, and the process returns to step

(1). (The pickup position does not change.)

(5)When the MEMORY key is pressed during playback, tracking servo ON/OFF is performed. (Even if the playback is stopped in servo OFF state, the servo is turned on when the playback is restored.)

Indication	The current pickup position and time are indicated. (When the

pickup is moved with the UP/DOWN key, the time at that point is indicated.)

Others

While the CD lid is open (LID-SW = "H"), the test mode is turned on but the operations of step (2) and subsequent steps are not performed. The operation of step (1) is performed.

Contents of error display

Error display		Contents of an error
Er	01	when TOC information cannot be read normally.
Er	02	When a PU-IN SW detection error occurs.

TUNER TEST MODE

The tuner test mode is intended to store the measurement frequency for adjustment and inspection in the preset memory CH without frequency adjustment in the case of tuner adjustment in the production line.

When the power is turned on while the PRESET (DOWN) key and BAND (PAUSE) key are held down together, the frequency for adjustment measurement of destination (specified according to AREA terminal) is preset-stored in the preset memory CH. (The frequency to be preset-stored for specific destination is as shown in the next page.)

– 7 –

QT-CD161/141

In the tuner test mode the band is FM, and the mode is FM STEREO in case of start-up.

As with the ordinary mode, when the PRESET key is pressed for 1ch of preset memory CH, maximum CH is set. When the PRESET key is pressed for maximum CH of preset memory CH, 1ch is set.

The BAND key is valid. As in the ordinary mode, the band/FM MONO/STEREO mode can be switched.

To exit from the tuner test mode, turn off the power to the microcomputer.

Indication

The indication is the same as that of ordinary operation. However, when the test mode is turned on, the indication shown left lights for one second.

Preset frequencies for various destinations (random preset memory)

BAND (CH)	U.S.A.	EUROPE	GENERAL 1	GENERAL 2
1	FM 87.5M	FM 87.50M	FM 87.50M	FM 87.5M
2	FM 108.0M	FM 108.00M	FM 108.00M	FM 108.0M
3	FM 98.0M	FM 98.00M	FM 98.00M	FM 98.0M
4	FM 90.0M	FM 90.00M	FM 90.00M	FM 90.0M
5	FM 106.0M	FM 106.00M	FM 106.00M	FM 106.0M
6	AM 530K	AM 522K	AM 531K	AM530K
7	AM1720K	AM1620K	AM1602K	AM1620K
8	AM 990K	AM 990K	AM 990K	AM 990K
9	AM600K	AM 603K	AM 603K	AM 600K
10	AM 1400K	AM 1404K	AM 1404K	AM 1404K
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Note:

The unit shown in table is Hz. K is x1000. M is x1,000,000.

The slash indicates that data are not stored in the memory.

FM is stereo mode.

LCD TEST MODE

When the LCD test mode is turned on, all the segments of LCD light.

Indication

– 8 –

QT-CD161/141

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.

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
SW102	RECORD/PLAYBACK	PLAYBACK
SW201	FUNCTION/POWER	TAPE—TUNER— CD/
		OFF—ON
SW202	X-BASS	OFF—ON
SW501	TUNER UP	OFF—ON
SW502	TUNER DOWN	OFF—ON
SW503	BAND	OFF—ON

REF. NO	DESCRIPTION	POSITION
SW504	MEMORY	OFF—ON
SW505	PRESET DOWN	OFF—ON
SW506	PRESET UP	OFF—ON
SW507	CD LID OPEN/CLOSE	OFF—ON
SW601	TAPE MAIN	OFF—ON
SW702	PICKUP IN	OFF—ON

FRONT

VIEW

E C B (S)(G)(D)

(1) (2) (3)

KTA1266 GR

KTA1273 Y

KTC3194 Y

KTC3199 GR

KTC8050 D

KRA102 M

KRA109 M

KRC104 M

KRC107 M

Figure 9 TYPES OF TRANSISTOR

– 9 –

QT-CD161/141

WAVEFORMS OF CD CIRCUIT

1	5ms	STOP	PLAY
	0.50 V
	IC801 20 F.E	FOCUS	SERCH

5ms 2 5.0 V

IC801 54 DRF

3

1

	3	0.5ms	CUE
		1.00 V
		HF
			1
	4	0.5ms	2
		5.0 V
		HFL
	5	0.5ms	3
		5.0 V
		TES

	3	0.5ms	REVIEW
		1.00 V
		H.F
			1
	4	0.5ms	2
		5.0 V
		HFL
	5	0.5ms	3
		5.0 V
		TES

	6	50ms	CUE
		10.0 V
		JP+
	7	50ms
		10.0 V
		JP-
	8	50ms
		0.50 V
		JP
	9	50ms
		1.00 V
		TE

6	0.5ms
	10.0 V

	JP+
7	0.5ms
	10.0 V
	JP-
8	0.5ms
	0.50 V
	JP
9	0.5ms
	1.00 V
	TE

	6	50ms	REVIEW
		10.0 V
		JP+
	7	50ms
		10.0 V
		JP-
	8	50ms
		0.50 V
		JP
	9	50ms
		1.00 V
		TE
	6	0.5ms
		10.0 V
		JP+
	7	0.5ms
		10.0 V
		JP-
	8	0.5ms
		0.50 V
		JP
	9	0.5ms
		1.00 V
		TE
	10	20ms	PLAY
		1.00 V
			NORMAL DISC
		SPO
			TN0=01
	11	20ms
		2.00 V
		CLV+
	10	50ms	PLAY
		1.00 V	TCD-712 (140mm)
		SPO	TN0=01
	11	50ms
		2.00 V
		CLV+
			PLAY
			TCD-712
	12	5s
		100mV
		SLD
			1
	12	0.5s
		100mV
		SLD
			1

– 10 –

QT-CD161/141

TO

MAIN

SECTION

+7.4V

(CD)

64 63 62 51

37

46 39 38 33 32

LCHO

11

43 XVDD

8

4

+5V

23 VDD

CQCK. COIN RWC. WRQ

2

6 VVDD

IC802

LC78622E

53

SERVO/SIGNAL

54

55

CONTROL

45 XIN

56

RES.

57

58

XL801

16.93MHz

44

XOUT

EFMO EFMIN CLV+ CLV– V/P HFL

TES

TOFF TGL

JP+ JP– SQOUT.

61

1

SELIAL CONTROL

9 10 12 13 14 15 16 17 18 19 20

+7.4V

44 43 40

~

32

DAT,

SLI SLC CV+

JP–

DRF

54

CL,

CE 53

1

30

7 8 9 22 25 24

LA9240M SERVO AMP.

DAT 52

CL 51

62

LDD

CLK

50

CONSTANT

DEF 49

IC803

IC801

VOLTAGE

Q804

+5V

64

VCC1

REGULATOR

LA6541

FOCUS/TRACKING

SLD 29

+5V

3

/SPIN/SLIDE

LASER

Q801

SLEQ 28

13

DRIVER

SPO 27

29

DRIVER

FIN2 FIN1

SL– SL+

FD 16

28

E F

TO 15

18

1

2

3

4

30 31

25 26 20 21

5

6

10 11

PICKUP UNIT

M

M

FOCUS COIL

TRACKING COIL

M701

M702

SPIN

SLIDE

MOTOR

MOTOR

TO MAIN

TO MAIN

SECTION

SECTION

Figure 11 BLOCK DIAGRAM (1/3)

– 11 –