HCD-MD555 - Sony Audio Service Manual (repair manual). Page 3

— 3 —

CAUTION

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

This appliance is classified as a CLASS 1 LASER product.
The CLASS 1 LASER PRODUCT MARKING is located on
the rear exterior.

Laser component in this product is capable of emitting radiation
exceeding the limit for Class 1.

The following caution label is located inside the unit.

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 0.5 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-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 0.75
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 2 V AC range are suitable.  (See Fig. A)

Earth Ground

AC
voltmeter
(0.75V)

1.5k

Ω

0.15

µ

F

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

To Exposed Metal 
Parts on Set

AC: 230V ~ 50/60Hz 90W: AEP, UK model
AC: 110 – 120/220 – 240V ~ 50/60Hz 90W

: Singapore, Malaysia, Hong Kong, Tourist model

AC: 120V 60Hz 90W: US model