Sharp qt cd 250 service manual

Page 1

QT-CDZSO

SHARP SERVICE MANUAL

No. $2014QTCD250/

QT-C D250

, - In the interests of user-salety the set should be restored to its
@ COM FE ' . . . original condition and only parts identical to those specilied should
be used.

DIGITAL AUDIO

/ CONTENTS \

IMPORTANT SERVICE NOTEST (FOR U.S.A. ONLY) ..
SPECIFICATIONS .....
NAMES OF PARTS
OPERATION MANUAL.
DISASSEMBLY ................................................................
REMOVING AND REINSTALLING THE MAIN PARTS
ADJUSTMENT ....................................
NOTES ON SCHEMATIC DIAGRAM .
TYPES OF TRANSISTOR ..................
SCHEMATIC DIAGRAM ..............
WIRING SIDE OF P.W.BOARD
WAVEFORMS OF CD CIRCUIT ..
TROUBLESHOOTING (CD SECTION) .
FUNCTION TABLE OF IC ......................
PARTS GUIDE/EXPLODED VIEW

PACKING OF THE SET (FOR U.S.A. ONLY)

-
This document has been published to be used

SHARP CORPORATION lor alter sales service only.

The contents are subject to change without notice.

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QT-CD250

TO THE OPERATION MANUAL.

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

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 orthat 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.

. 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 0.150F 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 tothechassis (antenna, metal cabinet,
screw heads, knobs and control shafts, escutcheon, etc.)
and measure the AC voltage drop across the resistor.

®

VTVM
-OAC SCALEO-

1.5k ohms
10W

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

AllcheckmustberepeatedwiththeAClinecord plugconnection
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
0 General 0 Compact disc player
Power source: AC 120 V, 60 Hz Type: Compact disc
DC 9 V [ "D" size (UM/SUM-1, R20 Signal Non-contact, 3-beam semi-conduc-
or HP-2) battery X 6] readout: tor laser pickup
DC 4.5 V [ "AA" size (UM/SUM»3, Audio
R6 or HP-7) battery X 3 for backup channels: 2
memory] Quantization: 16-bit linear quantization
Power Filter: 8-times oversampling digital filter
consumption: 12 W D/A converter: 1-bit D/A converter
Output power: FTC; 2.0 W min. RMS per channel Wow and Unmeasurable
into 4 ohms from 150 Hz to 20 flutter: (less than 0.001% W. peak)
:Hz, with go tmlofre than 10 % total . Radio
armonic is 0 ion.
RM8' 23 W/CH Frequency FM; 87.5 - 108 MHz
(DC operation, 10 % T.H.D.) "95: AMi530'1a720 kHz
Speakers: 4" (10 cm) full-range speaker x 2 . Tape recorder
Output Headphones; 16-50 ohms Frequency
terminals: (recommended; 32 ohms) response: 50 - 14,000 Hz (Normal tape)
Dimenstons: Width; 15-3/ (400 mm) . .
. ,, Signal/notse
Height; 6-1/4 (158 mm) . _
,. ratio. 50 dB
Depth; 8~3/8 (212 mm) Wow and
Weight: 6.0 lbs. (2.7 kg) Without batteries flutter: 0.25 % (WRMS)
Motor: DC 9 V electric governor
Bias system: AC bias
Erase
system: Magnet erase

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