JVC PCX-350 Service manual

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PC-XC350

SERVICE MANUAL

CD PORTABLE COMPONEMT SYSTEM

PC-XC350

Unit No. SP-PCXC350

contents

Safety precaution ------------------ 1-2 Block/Wiring Diagram ----------------- 1-16 Disassembly method -------------- 1-4 Circuit Diagram ------------------------- 1-18 Adjustment method ---------------- 1-6 PCB drawing ---------------------------- 1-20 TOC read ---------------------------- 1-11 Assembly -------------------------------- 1-22 Major IC Description ---------------1-12 Packing ----------------------------------- 1-32

Unit No. SP-PCXC350

Area Suffix

J-----USA

C-----CANADA

Unit No. SP-PCXC350

No. xxxxx

OCT 2001

PC-XC350

Safety Precautions

1. This design of this product contains special hardware and many circuits and components specially for safety purposes. For continued protection, no changes should be made ti the original design unless authorised in writing by the manufacturer. Replacement parts must be identical to those used in the original circuits. Services should be performed by qualified personel only.

2. Alterations of the design or circuitry of the product should not be made. Any design alterations of the product should not be made. Any design alterations or additions will void the manufacturer's warranty and will further relieve the manufacturer of responsibility for personal injury or property damage resulting therefrom.

3. Many eletrical and mechanical parts in the products have special safety-related characteristics. These characteristics are often not evident from visual inspection nor can the protection afforded by them necessarily be obtain by using replaement components rated for higher voltage, the Parts List of Service manual. Electrical components having such features ate identified by the shading on the schematics and by ( ) on the parts List in the Service Manual. The use of a substitute repalcement which does not have the same safety characteristics as the recommended replacement parts shown in the Parts List of Service manual may create shock, fire, or other hazards.

4. The leads in the products are routed and dressed with ties, clamps, tubing's, barriers and the like to be separated from live parts, high temperatures parts, moving parts and/or sharp edges for the prevention of electric shcok and fire hazard. When service is required, the original leat routing and dress should be observed, and it should be confirmed that they have been returned to normal, after re-assembling.

5. Leakage current check (Electrical Shock hazard testing) After re-assembling the product, always perform an isolation check on the exposed metap Parts of the product (antenna terminals, knobs, metal cabinet, screw heads, headphone jack, control shafts, etc.) to be sure the product is safe to operate without danger of electrical shock. Do not use a line isloation transformer during this check.

Plug the AC line cord directly into the AC outlet. Using a "Leakage Current Tester", measure the leakage current from each ecposed metal parts of the cabinet, particularly and exposed metal part having a return path to the chassis, to a known good earth ground. Any leakage current must not exceed 0.5mA AC (r.m.s.) Alternate check method Plug the AC line cord directly into the AC outlet. Use an AC voltmeter having, 1,000 ohms per volt or more sensitvity in the following manner. Connect a 1,500 ohm 10W resistor paralleled by a

0.15uF AC-type capacitor between an exposed metal part and a known good earth ground. Measure the AC voltage across the resistor with the AC voltmeter. Move the resistor connection to each exposed metal part, particularly and exposed metal part having a return path to te chassis and measure the AC voltage across the resistor. Now, reverse the plug in the AC outlet and repeat each measurement. Voltage measured Any must not exceed 0.75 V AC (r.m.s.). This corresponds to 0.5 mA AC (r.m.s.).

Warning

1. This equipment has been designed and manufactured to meet international safety standards.

2. It is the legal responsibility of the repairer to ensure that these safety standards are maintained.

3. repairs must be made in accordance with the relevant safety standards.

4. It is essential that safety critical components are replaced by approved parts.

5. It mains voltage selector is provided, check setting for local voltage.

CAUTION Burrs formed during moulding may be left over on some parts of the chassis. Therefore,

pay attention to such burrs in the case of performing repair of this system.

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PC-XC350

Preventing static electricity

Electrostatic discharge (ESD), which occurs when static electricity stored in the body, fabric, etc. is discharged, can destroy the laser diode in the traverse unit (optical pcikup). Take care to prevent this when performing repairs.

1.1. Grounding to prevent damage by static electricity

Static electricity in the work area can destroy the optical pickup (laser diode) in devicessuch as DVD players. Be careful to use proper grounding in the area where repairs are being performed.

1.1.1. Gound the workbench

1. Ground the workbench by laying conductive material (such as a conductive sheet) or an iron plate over it before placing the traverse unit (optical pickup) on it.

1.1.2. Ground yourself

Use an anti-static wrist starp to release and static electricity built up in your body.

1.1.3. Handling the optical pcikup

1. In order to maintain quality during transport and before installation, both sides of the laser diode on the replacement optical pickup are storted. After replacement, return the shorted parts to their original condition. (Refer to the text.)

2. Do not use a tester to check the condition of the laserdiode in the optical pickup. The tester's internal power source can easily destory the laser diode.

1.2. Handling the traverse unit (optical pickup)

Do not subject the traverse unit (optical pcikup) to strong shocks, as it is a sensitive, complex unit.

Cut off the shorted part of the flexible cable using nippers, etc. after replacing the optical pickup. For specific

details, refer to the replacement procdeure in the text. Remove the anti-static pin when replacing the traverse unit. Be careful not to take too long a time when attaching itto the connector.

3. Handle the flexible cable carefully as it may break when subjected to strong force.

It is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not return it.

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PC-XC350

Screw B.

Disaeesmbly method

Removing the rear panel

1. From behind the body, remove the eight screws A retaining the rear panel.

2. Then remove the two screws B retaining the rear panel.

3. Take out the rear panel from the body.

Note: Be careful of the FM antenna white wire, it is connection with the tuner PCB up side. You can directly take out from the tuner PCB. When you re-assembly the product, plug the FM antenna white wire into the Tuner PCB's "FM ANT" position.

Screw A.

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PC-XC350

Removing the CD mechanism

1. Remove the rear panel

2. Removing the two screws E retaing the 3CD mechanism cover.

3. Removing the crew F retaing the control PCB left side.

4. Remove the srews G retaing on the 3CD mechanism cover & the two screws H retaining on the control PCB

Removing the Main PCB

1. Remove rear panel

2. Remove the 3CD mechanism

3. Remove the four screws attaching the main PCB.

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PC-XC350

Adjustment method

Measurement instruments required for Tuner section adjustment

Voltage applied to tuner ----- +B:DC 5.7V

1. Low frequency oscillator VT: FM 2~5v / am 1.5~7.5v This oscillator should have a capacity to output Reference measurement ----- 26.1mV(0.866/3 0dB to 600 at an oscillation frequency of output 50Hz-20KHz Input positions ----- AM : Standard loop antenna

FM : TP1 (hot) and TP2 (GND)

2. Electronic voltmeter

3. Distorion meter

4. Frequency counter Standard measurement position of volumett

5. Wow & flutter meter

6. Test tape Bass ---------------------- Off TCC-112: tape speed and running unevenness (3KHz) EQ ----------------------- Flat TCC-140: Reference level (1KHz) UP and down adjustment of volume ----- Vol : 16 TCC-182A: Head angle (8KHz), playback frequency

characteristics (1KHz) and dubbing frequency Precautions for measurement charateristics (125Hz and 8KHz) 1. Direct connect to the IF sweeper output

side and 1 UF and 22 Kohm connect to the

7. Black tape sweeper input side. Same as FIG. 1. TYPE I : TDK-D60

8. Torque gauge : For play and tension FWD(CT-120m), and FF/REW(CT-F)

Measurement conditions

Power supply voltage----------AC 120V (60Hz) Reference output----------Speaker : 0.866V/3 2. The IF sweeper output level should be made as Headphone : 0.245V/32 low as possible within the adjusttable range. Reference frequency and -----1KHz, AUX : 450mV 3. Since the IF sweeper is a fixed device, there is no input level need to adjust this sweeper. Input for confirming recording and-----CD : -10dB 4. Since a ceramic oscillator is used, there is no need playback characteristics to perform and MIX adjustment. Measurement output terminal-----Speaker CN301 5. Since a fixed coil is used, there is no need to *Load resistance----------------------3 adjust the FM tracking.

6. The input and output earth systems are separated. In case of simuitaneously measuring the voltage in

Radio Input signal both of the input and output systems with an

electronic voltmeter for two channels, therefore, the

AM frequency ----------------400Hz earth should be connected particularly carefully. AM modulation-----------------30% 7. In the case of BTL connection amp., the minus FM frequency -----------------1 KHz terminal of speaker is not for earthing. Therefore, be FM frequency deviation --------22.5KHz sure not to connect any other earth terminal to this

terminal. This system is of an BTL system.

8. For connecting a dummy resistor when measuring the output, use the wire with a greater code sze.

9. Whenever any mixed tape is used, use the band pass filter (DV-12V)

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TUNER ADJUSTMENT

use a plastic screews driver for adjustments. Adjust the intermediate frequency of AM and FM to the frequency of cermic filter. Supply voltage: DC 12.0V Speaker impedance: 3 OHMS Function switch: RADIO

PC-XC350

a. AM adjustment BAND SELECT SWITCH : AM

ste Adjusting Tuning Adjustment

circuit Frequency Measurement input Measurement output parts

1 IF 1000 KHz AM Sweep Loop VTVM TP16 (H) T103

(450 KHz) Generator ANT Oscilloscope TP 8 (E)

2 Tuning 530 KHz Digital TP16 (H) T102 3 Coverage 1710 KHz Voltmeter TP 8 (E)

4 Tracking 600 KHz Am signal Loop VTVM TP12 (L) MW COIL 5 1500 KHz Generator ANT Oscilloscope TP11 (R) CT102

b. FM Adjustment BAND SELECT SWITCH : FM FM Dummy Antenna : 75 ohm unbalance

ste Adjusting Tuning Adjustment

circuit Frequency Measurement input Measurement output parts

1 IF FM Sweep TP4 (H) VTVM TP16 (H)

(10.7 MHz) 98.0 MHz Generator TP8 (E) Oscilloscope TP8(E) T104

2 Tuning 87.5 MHz Digital TP16 (H) 3 Coversage 108 MHz -- -- Voltmeter TP8(E) L104

4 Tracking 90.0 MHz FM Signal FM ANT VTVM TP12 (L) L103 5 106.0 MHz Generator TP1(E) Oscilloscope TP11 (R)

Input Connection Output Connection VTVM Oscilloscope

Output ConnectionInput Connection VTVM Oscilloscope

1.2+/-0.05V

Confirm 7.0+/-0.5V

Maximum

Confirm 1.4+/-0.1V

5.6+/-0.5V

Confirm with being

near by effective

sensitvity

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PC-XC350

ARRANGEMENT OF ADJUSTMENTS POSITION

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PC-XC350

Tape recorder section

Items Measurement Measurement method Standard Adjusting

conditions Values position

Confirmation Test tape 1 Playback the test tape TCC-182A (8KHz) Maximum Adjust the head of head angle : TCC-182A(8KHz) 2 With the recording & playback mechanism, output azimuth screw

Confirmation Test tape Adjust VR401 so that the frequency counter Tape speed VR401 of tape speed : TCC-112 (3KHz) reading becomes 3,010Hz +/-15Hz when of deck

Measurement output adjust the head azimuth screw so that the only terminal left and right output leavers become : Speaker terminal maximum, After adjustment, lock the head Speaker R/L azimuth at least by half turn. (Load resistance: 3 : Headphone terminal

playing back the test tape TCC-112 (3KHz) with :3,010Hz

playback and recording mechanism after +/-15Hz Measurement output ending forward winding of the tape. terminal : Headphone terminal

Referemce Values for Confirmation Items

Items Measurement

conditions Values position

Wow & flutter Test tape When the test tape TCC-112 (3KHz) has been 0.25% or

:TCC-112(3KHz) played back with the recording and playback less

mechanism at the beginning of forward (WRMS)

winding, the frequency counter reading of Measurement output wow & flutter should be 0.25% or less terminal (WRMS). :Headphone terminal

Measurement method

Standard Adjusting

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PC-XC350

Electrical Performance

Items Measurement Measurement method Standard Adjusting

conditions Values position

Adjustment of Mode: Playback 1 With the recording and playback recording blas mode mechanism, load the test tapes TDK-D60 current Recording mode TDK-D60, and set the mechanism to the 4.5 u A (Reference Test tape recording and pausing condition in advance. +/-0.5u A Value) TDK-D60

Adjustment of Reference frequency 1 with the recording and playback Output recording and :1KHz and 8KHz mechanism, load the test tapes (TDK-D60) deviation palyback (REF.:-10dB) and set the mechanism to the between frequency Test tape recording and pausing condition in 1KHz and characteristics TDK-D60 advance 8KHz

Measurement output 2 After connecting 100 in series to the terminal recorder head, measure the blas current : Both recording and with a valve voltmeter at both of the headphone terminals terminals

Measurement input 2 While repetitively inputting the reference :-1dB +/-2dB terminal frequency signal of 1KHz and 8KHz from : OSC IN OSC IN, record andplayback the tape.

3 While recording and playback the test tape Lch and Rch so that the output deviation between 1KHz and 8KHz from

-1dB +/-2dB

Reference Values for Electrical Function Confirmation Items

Items Measurement Measurement method Standard Adjusting

conditions Values position

Recording Playback 1 While changing over t and form BIAS 1 64KHz T201 blas Test tape and 2, confirm that the frequency is +/-6KHz frequency TDK-D60 changed.

Measurement 2 With the recording and playback terminal : BIAS TP on mechanism, load the test tape. P.C. board (TDK-D60), and set the

mechanism to the recording and pausing condition in advance. 3 Confirm that the BIAS TP frequency on the P.C. board is 64KHz +/-6KHz

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