DVP-NC875V
SAFETY CHECK-OUT
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-solderedLEAKAGE TEST
connections. Check the entire board surface for solder splashesThe AC leakage from any exposed metal part to earth ground and
and bridges.from all exposed metal parts to any exposed metal part having a
return to chassis, must not exceed 0.5mA (500 microampers).
2. Check the interboard wiring to ensure that no wires are ?pinched?
Leakage current can be measured by any one of three methods.
or contact high-wattage resistors.
3. Look for unauthorized replacement parts, particularly transistors,
1. A commercial leakage tester, such as the Simpson 229 or RCA
that were installed during a previous repair. Point them out to
WT-540A. Follow the manufacturers? instructions to use these
the customer and recommend their replacement.
instruments.
4. Look for parts which, though functioning, show obvious signs
2. A battery-operated AC milliammeter. The Data Precision 245
of deterioration. Point them out to the customer and recommend
digital multimeter is suitable for this job.
their replacement.
3. Measuring the voltage drop across a resistor by means of a VOM
5. Check the line cord for cracks and abrasion.
or battery-operated AC volmeter. The ?limit? indication is 0.75V,
Recommend the replacement of any such line cord to the
so analog meters must have an accurate low voltage scale. The
customer.
Simpson 250 and Sanwa SH-63Trd are examples of a passive
6. Check the B+ voltage to see it is at the values specified.VOM that is suitable. Nearly all battery operated
7. Check the antenna terminals, metal trim, ?metallized? knobs,digital multimeters that have a 2V AC range are suitable. (See
screws, and all other exposed metal parts for AC leakage. CheckFig. A)
leakage as described below.Unleaded solder
Boards requiring use of unleaded solder are printed with the lead-
free mark (LF) indicating the solder contains no lead.
To Exposed Metal(Caution: Some printed circuit boards may not come printed with
Parts on Setthe lead free mark due to their particular size.)
: LEAD FREE MARK
Unleaded solder has the following characteristics.
AC
Unleaded solder melts at a temperature about 40°C highter than
Voltmeter
1.5k 0.15 F
(0.75 V)ordinary solder.
Ordinary soldering irons can be used but the iron tip has to be
applied to the solder joint for a slightly longer time.
Soldering irons using a temperature regulator should be set to
about 350°C
Earth Ground
Caution: The printed pattern (copper foil) may peel away if the
heated tip is applied for too long, so be careful!
Fig.A. Using an Acvoltmeter to check AC leakage.
Strong viscosity
Unleaded solder is more viscous (sticky, less prone to flow) than
ordinary solder so use caution not to let solder bridges occur
WARNING!!
such as on IC pins, etc.
WHEN SERVICING, DO NOT APPROACH THE LASER EXIT WITH Usable with ordinary solder
THE EYE TOO CLOSELY. IN CASE IT IS NECESSARY TOIt is best to use only unleaded solder but unleaded solder may
CONFIRM LASER BEAM EMISSION, BE SURE TO OBSERVE
also be added to ordinary solder.
FROM A DISTANCE OF MORE THAN 25 cm FROM THE SURFACE
OF THE OBJECTIVE LENS ON THE OPTICAL PICK-UP BLOCK.
CAUTION:
The use of optical instrument with this product will increase eye
hazard.
CAUTION
Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous radiation
exposure.
SAFETY-RELATED COMPONENT WARNING!!ATTENTION AU COMPOSANT AYANT RAPPORT
A LA S�CURIT�!
COMPONENTS IDENTIFIED BY MARK OR DOTTED LINE
LES COMPOSANTS IDENTIF�S PAR UNE MARQUE SUR LES
WITH MARK ON THE SCHEMATIC DIAGRAMS AND IN
DIAGRAMMES SCH�MATIQUES ET LA LISTE DES PIECES SONT
THE PARTS LIST ARE CRITICAL TO SAFE OPERATION.
CRITIQUES POUR LA S�CURIT� DE FONCTIONNEMENT. NE
REPLACE THESE COMPONENTS WITH SONY PARTS WHOSE
REMPLACER CES COMPOSANTS QUE PAR DES PIESES SONY
PART NUMBERS APPEAR AS SHOWN IN THIS MANUAL OR
DONT LES NUM�ROS SONT DONN�S DANS CE MANUEL OU
IN SUPPLEMENTS PUBLISHED BY SONY.
DANS LES SUPP�MENTS PUBLI�S PAR SONY.
? 2 ? |
ACEC
