TFT LCD Color Computer Display
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 passive VOMs that are suitable.
Nearly all battery operated digital multimeters that have a 2 V AC range
are suitable. (See Fig. A)
After correcting the original service problem, perform the following safety
checks before releasing the set to the customer:
1. Check the area of your repair for unsoldered or poorly-soldered
connections. Check the entire board surface for solder splashes and
2. Check the interboard wiring to ensure that no wires are "pinched" or
contact high-wattage resistors.
3. Check that all control knobs, shields, covers, ground straps, and
mounting hardware have been replaced. Be absolutely certain that you
have replaced all the insulators.
4. Look for unauthorized replacement parts, particularly transistors, that
were installed during a previous repair. Point them out to the customer
and recommend their replacement.
5. Look for parts which, though functioning, show obvious signs of
deterioration. Point them out to the customer and recommend their
6. Check the line cords for cracks and abrasion. Recommend the
replacement of any such line cord to the customer.
7. Check the connector shell, metal trim, "metallized" knobs, screws, and
all other exposed metal parts for AC Leakage. Check leakage as de-
Fig. A. Using an AC voltmeter to check AC leakage.
To Exposed Metal
Parts on Set
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY SHADING AND MARK
! ON THE
SCHEMATIC DIAGRAMS, EXPLODED VIEWS AND IN THE
PARTS LIST ARE CRITICAL FOR SAFE OPERATION. REPLACE
THESE COMPONENTS WITH SONY PARTS WHOSE PART
NUMBERS APPEAR AS SHOWN IN THIS MANUAL OR IN
SUPPLEMENTS PUBLISHED BY SONY. CIRCUIT ADJUST-
MENTS THAT ARE CRITICAL FOR SAFE OPERATION ARE
IDENTIFIED IN THIS MANUAL. FOLLOW THESE PROCEDURES
WHENEVER CRITICAL COMPONENTS ARE REPLACED OR IM-
PROPER OPERATION IS SUSPECTED.
ATTENTION AUX COMPOSANTS RELATIFS À LA SÉCURITÉ!!
LES COMPOSANTS IDENTIFIÉS PAR UNE TRAME ET UNE
! SONT CRITIQUES POUR LA SÉCURITÉ. NE LES
REMPLACER QUE PAR UNE PIÈCE PORTANT LE NUMÉRO
SPECIFIÉ. LES RÉGLAGES DE CIRCUIT DONT L'IMPORTANCE EST
CRITIQUE POUR LA SÉCURITÉ DU FONCTIONNEMENT SONT
IDENTIFIÉS DANS LE PRÉSENT MANUEL.
PROCÉDURES LORS DE CHAQUE REMPLACEMENT DE
FONCTIONNEMENT EST SUSPECTÉ.
POWER SAVING FUNCTION
AUTOMATIC PICTURE QUALITY ADJUSTMENT