6557-03N/03S/43N/43S
SAFETY CHECK-OUT
(US Model only)
After correcting the original service problem, perform the fol-3. Measuring the voltage drop across a resistor by means of a
lowing safety checks before releasing the set to the customer:VOM or battery-operated AC voltmeter. The Olimit� indica-
1. Check the area of your repair for unsoldered or poorly-sol-tion is 0.75 V, so analog meters must have an accurate low-
dered connections. Check the entire board surface for soldervoltage scale. The Simpson 250 and Sanwa SH-63Trd are
splashes and bridges.examples of a passive VOMs that are suitable. Nearly all
2. Check the interboard wiring to ensure that no wires arebattery operated digital multimeters that have a 2 V AC
Opinched� or contact high-wattage resistors. range are suitable. (See Fig. A)
3. Check that all control knobs, shields, covers, ground straps,
and mounting hardware have been replaced. Be absolutelyWARNING!!
NEVER TURN ON THE POWER IN A CONDITION IN
certain that you have replaced all the insulators.
WHICH THE DEGAUSS COIL HAS BEEN REMOVED.
4. Look for unauthorized replacement parts, particularly tran-
sistors, that were installed during a previous repair. Point
SAFETY-RELATED COMPONENT WARNING!!
them out to the customer and recommend their replacement.
COMPONENTS IDENTIFIED BY SHADING AND MARK
5. Look for parts which, though functioning, show obvious
� ON THE SCHEMATIC DIAGRAMS, EXPLODED
signs of deterioration. Point them out to the customer and
VIEWS AND IN THE PARTS LIST ARE CRITICAL FOR
recommend their replacement.SAFE OPERATION. REPLACE THESE COMPONENTS
6. Check the line cords for cracks and abrasion. RecommendWITH SONY PARTS WHOSE PART NUMBERS AP-
PEAR AS SHOWN IN THIS MANUAL OR IN SUPPLE-
the replacement of any such line cord to the customer.
MENTS PUBLISHED BY SONY. CIRCUIT ADJUST-
7. Check the B+ and HV to see if they are specified values.
MENTS THAT ARE CRITICAL FOR SAFE OPERATION
Make sure your instruments are accurate; be suspicious of
ARE IDENTIFIED IN THIS MANUAL. FOLLOW THESE
your HV meter if sets always have low HV.PROCEDURES WHENEVER CRITICAL COMPONENTS
8. Check the antenna terminals, metal trim, Ometallized�ARE REPLACED OR IMPROPER OPERATION IS SUS-
knobs, screws, and all other exposed metal parts for ACPECTED.
Leakage. Check leakage as described below.
AVERTISSEMENT!!
NE JAMAIS METTRE SOUS TENSION QUAND LA
To Exposed Metal
Parts on SetBOBINE DE DEMAGNETISATION EST ENLEV?E.
ATTENTION AUX COMPOSANTS RELATIFS � LA
S?CURIT?!!
LES COMPOSANTS IDENTIFI?S PAR UNE TRAME ET
UNE MARQUE � SONT CRITIQUES POUR LA S?CURIT?.
AC
0.15 ?F1.5 kWVoltmeterNE LES REMPLACER QUE PAR UNE PIéCE PORTANT LE
(0.75 V)
NUM?RO SPECIFI?. LES R?GLAGES DE CIRCUIT DONT
LOIMPORTANCE EST CRITIQUE POUR LA S?CURIT? DU
FONCTIONNEMENT SONT IDENTIFI?S DANS LE
PR?SENT MANUEL. SUIVRE CES PROC?DURES LORS
Earth GroundDE CHAQUE REMPLACEMENT DE COMPOSANTS CRI-
TIQUES, OU LORSQUOUN MAUVAIS FONCTIONNE-MENT
Fig. A. Using an AC voltmeter to check AC leakage.
EST SUSPECT?.
LEAKAGE TEST
The AC leakage from any exposed metal part to earth ground
and from all exposed metal parts to any exposed metal part hav-
ing 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 manufacturersO instructions to
use these instruments.
2. A battery-operated AC milliammeter. The Data Precision
245 digital multimeter is suitable for this job.
� 2 � |
ACEC
