SLV-D500P (serv.man2) - Sony VCR Service Manual (repair manual). Page 2

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WARNING!!
WHEN  SERVICING,  DO  NOT  APPROACH  THE  LASER
EXIT  WITH  THE  EYE  TOO  CLOSELY.  IN  CASE  IT  IS
NECESSARY  TO  CONFIRM  LASER  BEAM  EMISSION,
BE  SURE  TO  OBSERVE  FROM  A  DISTANCE  OF
MORE   THAN   25  cm  FROM  THE  SURFACE  OF  THE
OBJECTIVE  LENS  ON  THE  OPTICAL  PICK-UP  BLOCK.
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!!
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
PUBLISHED  BY  SONY.
CAUTION:
The use of optical instrument with this product will increase eye
hazard.
Fig. A.
Using an AC voltmeter to check AC leakage.
1.5 k
0.15 
µ
F
AC
voltmeter
(0.75 V)
To Exposed Metal
Parts on Set
Earth Ground
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
0.75V, 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)
1. Check the area of your repair for unsoldered or poorly-soldered
connections.  Check the entire board surface for solder splashes
and bridges.
2. Check the interboard wiring to ensure that no wires are “pinched”
or contact high-wattage resistors.
3. Look for unauthorized replacement parts, particularly transistors,
that were installed during a previous repair.  Point them out to the
customer and recommend their replacement.
4. Look for parts which, though functioning, show obvious signs of
deterioration.  Point them out to the customer and recommend
their replacement.
5. Check the line cord for cracks and abrasion. Recommend the
replacement of any such line cord to the customer.
6. Check the B+ voltage to see it is at the values specified.
7. Check the antenna terminals, metal trim, “metallized” knobs,
screws, and all other exposed metal parts for AC leakage.  Check
leakage as described below.
SAFETY CHECK-OUT
After correcting the original service problem, perform the following
safety checks before releasing the set to the customer:
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