Sony rcd w 7 v service manual

Page 2

RCD-W7V

NOTES ON HANDLING THE OPTICAL PICK-UP
BLOCK OR BASE UNIT

The laser diode in the optical pickiup block may suffer electrostatic
breakidown because of the potential difference generated by the
charged electrostatic load, etc. on clothing and the human body.
During repair, pay attention to electrostatic breakdown 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.

NOTES ON LASER DIODE EMISSION CHECK

The laser beam on this model is concentrated so as to be focused on
the disc reflective surface by the objective lens in the optical pick
up block. Therefore, when checking the laser diode emission, ob»
serve from more than 30 cm away from the objective lens.

CAUTION

The use of optical instruments with this product will increase eye
hazard.As the laser beam used in this Compact Disc Recorder is
harmful to eyes, do not attempt to disassemble the cabinet.
Refer servicing to qualified personnel only.

CAUTION _ _
VISIBLE LASER RADIATION This label 15 located on the rear
WHEN OPEN AND panel of your recorder.
INTERLOCK DEFEATED.

DO NOT STARE INTO BEAM.

CAUTION

Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous rav
diation exposure.

Notes on chip component replacement

I Never reuse a disconnected chip component.

I Notice that the minus side of a tantalum capacitor may be
damaged by heat.

Flexible Circuit Board Repairing

I Keep the temperature of soldering iron around 270°C
during repairing.

I Do not touch the soldering iron on the same conductor of the
circuit board (within 3 times).

I Be careful not to apply force on the conductor when soldering
or unsoldering.

SAFETY-RELATED COMPONENT WARNING I!

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

SAFETY CH ECK-OUT

After correcting the original service problem, perform the follow~
ing safety checks 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

The AC leakage from any exposed metal part to 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). Leakv

age current can be measured by any one of three methods.

1. Acommercial leakage tester, such as the Simpson 229 or RCA
WT7540A. Follow the manufacturers' instructions to use these
instruments.

2. A batteryoperated AC milliammetcr. The Data Precision 245
digital multimeter is suitable for thisjob.

3. Measuring the voltage drop across a resistor by means of a VOM
or batteryvoperated AC voltmeter. The limit" indication is 0.75
V, so analog meters must have an accurate lowivoltage scale.
The Simpson 250 and Sanwa SHIGSTrd are examples of a pas
sive VOM that is suitable. Nearly all battery operated digital
multimeters that have a 2V AC range are suitable. (See Fig. A)

To Exposed Metal
Pans on Set

A C
voltmeter

(0. 75 V)
'=' Earlh Ground

Fig. A. Using an AC voltmeter to check AC leakage.