SLV-D100 - Sony VCR Service Manual (repair manual). Page 4

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1. Be sure that all of the built-in protective devices are

replaced. Restore any missing protective shields.

2. When reinstalling the chassis and its assemblies, be sure

to restore all pretective devices, including : control knobs
and compartment covers.

3. Make sure that there are no cabinet openings through

which people--particularly children--might insert fingers
and contact dangerous voltages. Such openings include
the spacing between the picture tube and the cabinet
mask, excessively wide cabinet ventilation slots, and
improperly fitted back covers.

If the measured resistance is less than 1.0 megohm or
greater than 5.2 megohms, an abnormality exists that
must be corrected before the unit is returned to the
customer.

4. Leakage Current Hot Check (See Fig. 1-1) :

Warning : Do not use an isolation transformer during this
test. Use a leakage current tester or a metering system
that complies with American National Standards Institute
(ANSI C101.1, Leakage Current for Appliances), and
Underwriters Laboratories (UL Publication UL1410,
59.7).

5. With the unit completely reassembled, plug the AC line

cord directly the power outlet. With the unit’s AC switch
first in the ON position and then OFF, measure the
current between a known erath ground (metal water pipe,
conduit, etc.) and all exposed metal parts, including :
antennas, handle brackets, metal cabinets, screwheads
and control shafts. The current measured should not
exceed 0.5 milliamp. Reverse the power-plug prongs in
the AC outlet and repeat the test.

6. Antenna Cold Check :

With the unit’s AC plug disconnected from the AC
source, connect an electrical jumper across the two AC
prongs. Connect one lead of the ohmmeter to an AC
prong.
Connect the other lead to the coaxial connector.

7. Some semiconductor (“solid state”) devices are easily

damaged by static electricity.
Such components are called Electrostatically Sensitive
Devices (ESDs); examples include integrated circuits and
some field-effect transistors. The following techniques
will reduce the occurrence of component damage caused
by static electricity.

8. Immediately before handling sny semiconductor

components or assemblies, drain the electrostatic charge
from your body by touching a known earth ground.
Alternatively, wear a discharging Wrist-strap device. (Be
sure to remove it prior to applying power--this is an
electric shock precaution.)

9. Design Alteration Warning :

Never alter or add to the mechanical or electrical design
of this unit. Example : Do not add auxiliary audio or
video connectors.
Such alterations might create a safety hazard.
Also, any design changes or additions will void the
manufacturer’s warranty.

10. Never defeat any of the B+ voltage interlocks.

Do not apply AC power to the unit (or any of its
assemblies) unless all solid-state heat sinks are correctly
installed.

11. Always connect a test instrument’s ground lead to the

instrument chassis ground before connecting the positive
lead; always remove the instrument’s ground lead last.

Fig1. AC Leakage Test

DEVICE

UNDER

TEST

(READING SHOULD

NOT BE ABOVE

0.5mA)

LEAKAGE

CURRENT

TESTER

EARTH

GROUND

TEST ALL

EXPOSED METER

SURFACES

ALSO TEST WITH
PLUG REVERSED

(USING AC ADAPTER
PLUG AS REQUIRED)

2-WIRE CORD