Sony CMA-10 Service Manual page 2

SAFETY CHECK-OUT
After correcting the original service problem, perform
the following safety checks before releasing the set to
the customer:
Check the 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 meta! part to earth
ground and from all exposed metal parts to any ex-
posed metal part having a return to chassis, must not
exceed 0.5 mA (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-S40A. 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
0.15 uF voltmeter
7 (0.75 V)
= Earth Ground
Using an AC voltmeter to check AC leakage.