CFD-575, CFD-577 - Sony Audio Service Manual (repair manual). Page 3

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The laser diode in the optical pick-up block may suffer electro-
static breakdown 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.

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 emis-
sion, observe more than 30 cm away from the  objective lens.

On repairing CD section, playing a disc without the CD lid, use
Chuck Plate Jig.

r

 Code number of Chuck Plate Jig : X-4918-255-1

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.

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 0.5mA (500 microampers).
Leakage current can be measured by any one of three methods.
1. A commercial leakage tester, such as the Simpson 229 or RCA

WT-540A. Follow the manufacturers’ instructions to use these
instruments.

2. A battery-operated AC milliammeter. The Data Precision 245

digital multimeter is suitable for this job.

3. Measuring the voltage drop across a resistor by means of a VOM

or battery-operated AC voltmeter. The “limit” indication is 0.75V,
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 a 2V AC range are suitable. (See Fig. A)

1. Press CD open knob.
2. Open the lid for CD.
3. Push on SWITCH (S702) as following figure.
4. Confirm the laser diode emission while observing the objecting

lens. When there is no emission, Auto Power Control circuit or
Optical Pick-up is broken.
Objective lens moves up and down once for the focus search.

AC
voltmeter
(0.75V)

To Exposed Metal
Parts on Set

Earth Ground

0.15   F  

µ

1.5k

Ω

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

Laser diode

Insert a precision
screwdriver and push
SWITCH (S702)