Jvc RCQW 33 Service Manual

Page 1

RC - QW33 C/J U

JVD
SERVICE MANUAL

RC -QW33 C/J/U

Contents

1. Safety Precautions ...................................... page 2
2. Safety Precaution about RC - QW33 --------------------- 3
3. Main Features --------------- --6
4. Specifications ...................................................... 6
5, Instrucfionqfixtract) ............................................. 6
6, Location of Main pans ............ . ........ . .................. 21
7. Ramayai of Main Parts ............................. 22
8 Main Adjustment».

9. Block Diagram--

@figfi

DIGITAL AUDIO

Area Suffix

~-Other areas

10, Troubleshooting ............................................... 35
11. Analytic Drawing and Parts List -------------------------- 40
12. Standard Schematic Diagram ---------------------------- 47
13. Wiring Connectians --------- 54
14, [c Block Diagram ............................................. 55
15. Location of P.C. Board Pans .............................. 58
16. Eiectrical Parts List ........................................... 62
17. Illustration of Packing and Pans List ------------------- 7|
1 8_ Accessories ........................................ Back cover

No. 1915
October 1994

Page 2

8. Main Adjustments

I Test Instruments required for adjustment
1. Low frequency oscillator
( Frequency range: 50Hz to 20kHz)
(Output: 0 st across 600 Q terminating resistor)
2. Attenuator( Impedance : 600 S2 )

3. Test Tapes
VTT712 ................. n... For tape speed,wow and
flutter measurement
VTT724 .. 'For playback output level measurement

VTI736 ----- For playback frequency response check
response check
VTT703 ---------------- For head azimuth adjustment
4. Blank tapes
Normal : UR
Chrome : AC224
5. Electronic voltmeter,
6. Distortion meter
7. Frequency counter
8. Wow and flutter meter
9. Torque gauge: CTG ~ K

( Cassette type) ------- For mechanism adjustment

I Measuring conditions (Amplifier section)

Supply voltage -------------- AC120V (60Hz):C/J version
AC1 10~127l220~240V(50/60Hz):U Version
Reference output level :Speaker

0 st (0.775V) / 3 Q

: Headphone

- 1o st (0.245V)/ 32 Q
Reference input level : - 21st supplied to test point
Standard test frequency- . ............................. 1 kHz
Output measuring point ----------------- Speaker terminal

: Dummy load 3 9 ,Test point CN993
or headphone(32 Q )
0 Standard position of switches
Function switch ........ . .............................. TAPE
Mode switch ................. . ..................... STEREO

RC , QW33 C/J/U

0 Standard position of controls

Tone ............................................. Flat position

Super Bass, .............................................. ON

Main volume adjust -------------- 0 st output position
0 Test remarks

1. Negative side of the input and output terminals of the
testing set, shall be isolated from each other. The
negative side should not be commonly connect ed
when a 2channel electronic voltmeter is connected.

2.A dummy load shall be connected to the output
terminal and the lead wires of dummy load shall be

as thick as possible.

I Measuring condition (Tuner section)

Power supply voltage to tuner ------------------ DC 5.7V
Reference output ~~~~~~~ Speaker : 50mW(0.39 V / 3 Q )
Headphon : 0.06V/ 32 9
AM modulation ..................... .. u. 400HZ, 30%
FM modulation ------------------ 400Hz deviation 22.5kHz
0 Standard position 01 switches and controllers
Function ............................................ RADIO
Mode .................. . ....................... STEREO

0 Remarks for alignment

1. Connect 30 pF capacitor and 33 k 9 resistor to the
output terminal of the IF sweeper in series while
0.082 ,u F capacitor and 100k 9 resistor to the input
terminal in series.

2.Set the output level of the IF sweeper as low as
adjustable.

3.lF alignment is not necessary for both AM and FM
MPX alignment is not necessory either. All IFTs and

MPX coil are non- adjusting type.

(No.1915) 27