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MODEL IDENTIFICATION-“ Rear View -“
Notes on chip component replacement
- Never reuse a disconnected chip component.
- Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.
Flexible Circuit Board Repairing
- Keep the temperature of the soldering iron around 270 ËšC during
repairing.
- Do not touch the soldering iron on the same conductor of the
circuit board (within 3 times).
- Be careful not to apply force on the conductor when soldering or
unsoldering.
Fig. A. Using an AC voltmeter to check AC leakage.
1.5 k -„¦ 0.15 µF AC
voltmeter
(0.75 V) To Exposed Metal
Parts on Set
Earth Ground
SAFETY CHECK-OUT
After correcting the original service problem, perform the follow-
ing 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 microamperes.).
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 pas-
sive VOM that is suitable. Nearly all battery operated digital
multimeters that have a 2 V AC range are suitable. (See Fig. A)
Par t No.
Model
DB940: US model
DB940: Canadian model
E model
Chinese model
Australian model
DB940: AEP and UK models
DB840: US model
DB840: AEP and UK models
DB840: Canadian model
Par t No.
4-227-151-0s
4-227-151-1s
4-227-151-2s
4-227-151-3s
4-227-151-4s
4-227-151-5s
4-227-151-7s
4-227-151-8s
4-227-151-9s
ATTENTION AU COMPOSANT AYANT RAPPORT
Ã- LA SÉCURITÉ!
LES COMPOSANTS IDENTIFIÉS PAR UNE MARQUE 0
SUR LES DIAGRAMMES SCHÉMATIQUES ET LA LISTE
DES PIÈCES SONT CRITIQUES POUR LA SÉCURITÉ
DE FONCTIONNEMENT. NE REMPLACER CES COM-
POSANTS QUE PAR DES PIÈCES SONY DONT LES
NUMÉROS SONT DONNÉS DANS CE MANUEL OU
DANS LES SUPPLÉMENTS PUBLIÉS PAR SONY. SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK 0 OR DOTTED
LINE WITH MARK 0 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.
