Sony TC-WR990 - Safety Checks and Precautions; AC Leakage Testing Procedure; Safety-Related Component Identification

SAFETY CHECK-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 0.5mA (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-S540A. 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.
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK A OR DOTTED
LINE WITH MARK A ON THE SCHEMATIC DIAGRAMS
AND IN THE PARTS LIST ARE CRITICAL TO SAFE
OPERATION. REPLACE THESE COMPONENTS WITH
SONY PARTS WHOSE PART NUMBERS APPEAR AS
SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUB-
LISHED BY SONY.
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 pF voltmeter
Prod (0.75 V)
= £arth Ground
Using an AC voltmeter to check AC leakage.
ATTENTION AU COMPOSANT AYANT RAPPORT
A LA SECURITE!
LES COMPOSANTS IDENTIFIES PAR UNE MARQUE /\
SUR LES DIAGRAMMES SCHEMATIQUES ET LA LISTE
DES PIECES SONT CRITIQUES POUR LA SECURITE
DE FONCTIONNEMENT. NE REMPLACER CES COM-
POSANTS QUE PAR DES PIECES SONY DONT LES
NUMEROS SONT DONNES DANS CE MANUEL OU
DANS LES SUPPLEMENTS PUBLIES PAR SONY.
SECTION 1
GENERAL
1-1. IDENTIFYING THE PARTS
Front Panel
This section is extracted from
instruction manual.
*Remote control sensor
(The illustration shows the TC-WR590.)
For details, refer to the page number indicated in
parenthesis.
[1] POWER switch
[2] Deck A
[3] COUNTER RESET button (deck A)
[4] DIR (direction) MODE switch
(pages 7, 8, 10 and 14)
[5] DOLBY NR (Dolby noise reduction) switch
(pages 7 and 10)
[6] Display panel
[7] SYNCHRO DUBBING buttons (page 14)
HIGH SPEED button
NORM (normal) SPEED button
[8] BALANCE control (page 10)
[9] REC (recording) LEVEL control (pages 10 and 11)
[10] COUNTER RESET button (deck B)
fii] Deck B
12] 4 (eject) button (deck B)
[13] HEADPHONES (headphones) jack (stereo phone
jack) (WR590 only)
Tape operation buttons
4 (leftward fast winding) button
>> (rightward fast winding) button
(stop) button
~“@ (reverse play) button
bb (forward play) button
Il PAUSE button (deck B only)
OQ REC MUTE (record muting) button (deck B only)
(page 13)
@ REC (recording) button (deck B only)
[15] & (eject) button (deck A)
*Remote controi sensor
You can remotely control this cassette deck with:
— Aremote commander that came with a Sony amplifier or
receiver if it has the lal mark and cassette deck control
capability.
— Any optional Sony remote commander with the lal mark
and cassette deck control capability.