Sony CDP-C245 - SAFETY CHECK-OUT; AC Leakage Test Procedure

MODEL IDENTIFICATION
—Model Number Label—
CDP-C235
CDP-C335
| SONY. woonn.WZ7Z
COMPACT DISC PLAYER
WLLL LLL
US, Canadian model: AC: 120V 60Hz
UK, Australian model: AC: 240V~50/60Hz
AEP model: AC: 220-230V~50/60Hz
E model: AC: 110-120V, 220-240V~50/60Hz
UP BLOCK OR BASE UNIT
The laser diode in the optical pick-up block may
suffer electrostatic breakdown because of the poten-
tial difference generated by the charged electrostatic
load, etc. on clothing and the human body.
During repair, pay attention to electrostatic break-
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.
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, observe from more than 30cm away from the
objective lens.
SAFETY CHECK-OUT
After correcting the original service problem,
perform the following 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 TEST
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 instru-
ments.
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 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 a 2V AC range are
suitable. (See Fig. A)
To Exposed Metal
Parts on Set
AC.
voltmeter
as (0.75 V)}
= Earth Ground
Using an AC voltmeter to check AC leakage.