Sony ta h 500 service manual

Page 2

TA-H500

SAFETY CH ECK-OUT

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.

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 0.5 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-54OA. 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 0,75V, 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)

To Exposed Metal
Parts on Set

AC
0.15;.4F 1.5 ksz voltmeter
(0. 75 VI

'._J

1: Earth Ground

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

SECTION 1

GENERAL

1-1. PARTS IDENTIFICATION

E SYSTEM POWER switch and STANDBY
indicator
It remains lit as long as the AC power
cord is connected to a wall outlet.

[3 DEMO button

[E] DISPLAY button

E HEADPHONES jack (stereo minijack)

IE WAKE UP button

E] PROGRAM FUNCTION button

E! DSP button and PRESET and DIRECT
indicators

E] DYNAMIC SOUND bullon

El Display window

Function selectors

E] VOLUME control

E DBFB (Dynamic Bass Feedback) button

IE] BALANCE button

E] CURSOR CONTROL buttons

El MEMORY button

ONIOFF button

[it PRESENCE SURROUND button

PARAMETRIC EOUALIZER button