Sony Trinitron Multiscan CPD-1302 - Page 54

CPD-1302
ELECTROCUTIUN
S TENSION, UN
r DOlT ETRE
;T DIRECTEMENT
TEUR.
ELATIFSA LA
UNE TRAME ET
'AS DE PRINCIPE,
STES
DE PIECES
IQUE POUR LA
NE LES REM·
; SONY
DONT LE
~NS LE PRESENT
TS
PUBLIES PAR
DONT L'IMPOR-
, SECURITE DU
FIES DANS LE
DCEDURES LORS
E COMPOSANTS
~IS FONCTIONNE·
CPD-1302
SAFETY CHECK-OUT
(US Model Only)
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 bridges.
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, par-
ticularly 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 replace-
ment.
6. Check the line cord for cracks and ahrasion.
Recommend the replacement of any such line
cord
to the customer.
7. Check the condition of the monopole antenna
(if any) .
Make sure the end
is not broken off, a nd has
the plastic cap on it. Point out the danger of
impalement on a broken antenna to the
customer, and recommend the antenna's
replacement.
8. Check the B+ and HV to see they are at the
values specified. Make sure your instruments
are accurate; be suspicious of your HV meter
if sets always have low HV.
9. Check the
antenna terminals, metal trim,
"metallized" knobs, screws, and all other
exposed metal parts for AC leakage. Check
leakage as described below.
To Exposed Metal
Parts
on Set
-=- Earth Ground
AC
voltmeter
(0.75 V)
Fig. A. Using an AC voltmeter to check AC leakage.
"
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 microampers). Leakage
current can be measured by anyone of three
methods .
1. A
commercial leakage tester, such as the
Simpson 229 or RCA WT-540A. Follow the
manufacturers' instructions to use these instru-
ments.
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 YOM or battery-operated AC. volt-
meter. 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 YOM that
is suitable . Nearly all battery operated digital
multimeters that have a 2 V AC range are
suitable. (See Fig. A)
HOW TO FIND A GOOD EARTH GROUND
A cold-water pipe is guaranteed earth ground; the
cover-plate retaining screw on most AC outlet boxes is
also
at earth ground . If the retaining screw is to be
used
as your earth-ground, verify that it is at ground
by measuring the resistance between it and a cold-
water pipe with an ohmmeter. The reading should be
zero
ohms. If a cold-water pipe is not accessible,
connect a 60-100 watts trouble light (not a neon
lamp) between the hot side of the receptacle and the
retaining screw. Try both slots, if necessary, to locate
the hot side of the line, the lamp should light at
normal brilliance if the screw is at ground potential.
(See Fig. B)
Trouble Ligh t
-: AC Outlet Box
Ohmmeter
Cold·water Pipe
Fig. 8. Checking for earth ground.
Iv. SW. FREQ Adjustment I
SECTION 1
CIRCUIT ADJUSTMENTS
1. Input the EGA signal to the monitor.
2.
Set the select switches position and VR adjust-
ment.
1) Digital voltage meter connect the probe between
TP2 and ground on the BA board.
Note: CONTRAST MINIMUM (Right side of
monitor)
2) Set the switches of the back side.
Note: D2-ANALOG
3) Adjust RV306 (V. SW. FREQ) for 6.10 V tolerance
0.02 V.
4) Set the switches of the back side.
Note: D2-DIGIT AL
5) Adjust RV307 (50/60) for 6.80 V tolerance
0.02 V.
6) After modification, adjust V. SIZE for VGA.
TP2 AND RV POSITION
BA
SW POSITION
D1
• TP2
o RV306
o RV307
NOR D2
(v. SW. FREO)
(50/60)
DIGITAL
Cy
ANALOG
CPD-130~