Sony CDP 790 Service Manual

Page 1

SERVICE MANUAL

U8 Model

Compact disc player
Frequency response
Signal to noise ratio
Dynamic range
Harmonic distortion
Channel separation

Outputs

LINE OUT
(phono jacks)

DIGITAL OUT (OPTICAL)
(optical output connector)

PHONES
(stereo phone jack)

General

Power requirements
Power consumption

Dimensions
(approx. including
projections)

Weight (approx)

Model Name Using Similar Mechanism

CDP-l90/39O

CD Transport Mechanism Type

CDM14-5BDl

Optical Pick-Up Block Type

BU-5BD1

SPECIFICATIONS

2 Hz 7 20 kHz:0.3 (18
More than 104 dB
More than 97 dB
Less than 0.003%
More than 98 dB

Output level 2 V (at 50 kilohms)
Load impedance over 10 kilohrns

Wave length 660 nm
Output level - 18 dBm

Output level max. 15 mW
Load impedance 32 ohms

120 V AC, 60Hz
14W

430x 110x280 mm (w/h/d)
(17><4/o><11/o inches)

318 kg (8 lbs 702)

Supplied accessories

Audio cord
Remote commander 1
R6 (size AA) batteries 2

Remote commander (RM-D290)

hemote control system Infrared control

1 (2 phone plugs - 2 phono plugs)

3 V DC with two R6 (size AA) batteries

Power requirements

Dimensions Approx 67 X 18 X 175 mm (w/h/d)
(23/t>< 7 inches)

Weight Approx. 150 g (5.3 oz)

Including batteries

Design and specifications subject to change without notice.

SAFETY-RELATED COMPONENT WARNING"

COMPONENTS IDENTIFIED BY SHADING AND MARK

A ON THE SCHEMATIC DIAGRAMS AND IN THE
PARTS LIST ARE CRITICAL TO SAFE OPERATION.
REPLACE THESE COMPONENTS WITH SONV PARTS
WHOSE PART NUMBERS APPEAR AS SHOWN IN THIS
MANUAL OR IN SUPPLEMENTS PUBLISHED BY SONV.

COMPACT DISC PLAYER

SONY;

Page 2

GDP-790

SAFETY CHECK-OUT 3. Measuring the voltage drop across a resistor by
means of a VOM or battery-operated AC volt-
meter. The limit indication is 0.75 V, so
analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa
SH-63Trd are examples of a passive VOM that
is suitable. Nearly all battery operated digital
multimeters that have at 2V AC range are
suitable. (See Fig. A)

After correcting the original service problem,
perform the following safety check before releasing
the set to the customer:

Check the antenna terminals, metal trim, metallized
knobs, screws, and all other exposed metal parts for
AC leakage. Check leakage as described below.

LEAKAGE TEST

To Exposed Metal

The AC leakage from any exposed metal part to Parts on Set

earth ground and from all exposed metal parts to any

exposed metal part having a return to chassis, must
not exceed 0.5 mA (500 microampers). Leakage -l
current can be measured by any one of three r
methods. 0.15M 1.5km / foe/imam
l. A commercial leakage tester, such as the > [0475.
Simpson 229 or RCA WT-540A. Follow the
manufacturers instructions to use these instru-
mems.

"-3 Earth Ground

2. A battery-operated AC milliammeter, The Data
Precision 245 digital multimeter is suitable for
this job.

F (g. A. Using an AC voltmeter to check AC leakage.

PROTECTION OF EYES FROM LASER BEAM DURING SERVICING

This set employs a laser. Therefore, be sure to follow 1. Laser Diode Properties
carefully the instructions below when servicing. Material: Ga Al A5

O
o Wavelength: 780 mm
0 Emission Duration: continuous
CAUTION 0 Laser Output Power: less than 44.6 uW*
. This output is the value measured at a distance of
Use of controls or adjustments or performance 200 mm from the objective lens surface on the
of procedures other than those specified herein Optical Pick~np Block.
may result in hazardous radiation exposure.

2. During service, do not take the Optical Pick-up Block
apart, and do not adjust the APC circuit. If there is a
breakdown in the APC circuit (including laser diode),
replace the entire Optical Pick-up Block (including
APC board).

.-...-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-..

SERVICING NOTE

NOTES ON HANDLING THE OPTICAL pch. NOTES ON LASER DIODE EMISSION CHECK
UP BLOCK on BASE unn- The laser beam on this model is concentrated so as to be
focused on the disc reflective surface by the objective lens in
The laser diode in the optical picloup block may the optical pick-up block. Therefore, when checking the laser
suffer electrostatic breakdown because of the poten- diode emission, observe from more than 30cm away from the
tial difference generated by the charged electrostatic objective lens.

load, etc. on clothing and the human body.

During repair, pay attention to electrostatic brealo
down and also use the procedure in the printed
matter which is included in the repair parts.

The flexible board is easily damaged and should be
handled with care.