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3-8. SAFETY RELATED ADJUSTMENTS
BLANKING
CIRCUIT OPERATION CHECK
( 8 R534)
Be sure to perform
this adjustment when replacing
the following parts (marked
Ciiil
on the schematic.)
0713, 0714, D707, R728 }
R759, R760, R761, R162,
on C board
R763, Rll0,
R774, R715
0507, D500, D501, R532,}
Db
d
R534, R536, R584
on
oar,
02012, R2141, R2143,
}
B b
d
R2144
on
oar,
1. Input a monoscope signal.
picture
} MAX
BRT
2. Confirm that the BLANKING
circuit operates
when 125.5V DC is applied to +B line from an
external power supply. (Raster goes not.)
digital multi-meter
D
+
digital multi-meter
D
+
-27-
KV-25DXR
RM-727/APM-X3U
I
HOLD DOWN OPERATION
CHECK (
8
R573)
Be sure to perform
this adjustment
when replacing
the following parts (marked
Ciiill
on the schematic).
R533, R560, R570, R571, R572, R573, R574,
R582,
R583,
R1500,
R1502,
R1503,
R1504,
R1522, R1530, D518, D522, 0512, 0514, 0515,
IC500.
KV-25DXR
RM-727/APM-X3U
DETECTION
VOLTAGE
OPERATION
CHECK
I
1. Input a dot signal.
PICTURE, BRT MIN
ACpower
120V±2VAC
2. Check that TP85 voltage value is 14.0
±
1V DC.
3. Check that HOLD DOWN operates when 16.30
+O
V DC is applied to TP85 from external
-0.05
power supply. (/ABL
=
190
±
10mA)
4. Check that HOLD DOWN does not operate when
15.65 ~~·
05
v
DC is applied to TP85 from an
external power supply.
5. Input a WHIT signal.
PICTURE, BRT MAX
ACpower
120V±2VAC
6. Confirm
that the HOLD DOWN circuit operates
when 15.27 ~~_
05
v
DC is applied to TP85 from
an external
power
supply.
(Raster goes out.)
(IABL
=
16.50
±
10µA)
7.
Confirm
that the HOLD DOWN circuit does not
+0.05
.
operate when
14.47 _
0
V de ts applied to
TP85 from an external power supply.
£;tj
:
=D=Fboard
Setacpfaug
variable
auto-transformer
D'
I
I
I
fl.
I
Ammeler
I
I
I.OmA DC
I
:
81
range
A
I
ABL
L ____
_J
-
IC901
T901 FBT
I
ABL
Disengage the ABL terminal of FBT from the foil
the un-soldering and connect negative probe to the
ABL PIN of FBT.
I
OVER VOLTAGE PROTECTION CIRCUIT CHECK
I
1. Input a monoscope signal.
PICTURE)
BRT
MAX
COLOR
2. Check that +B voltage is less than 141.5V during
AC 133V input.
3. Short D board R513.
4. Apply
154
±
3V DC to +Bline
from an external
power supply, and confirm
that the OVP circuit
operates.
5. Apply
141V DC to the +B line and switch the
channel. Confirm that the OVP circuit does not
operate when power is turned ON and OFF during
dot signal.
D-3
-
-
-
140V
-
Y-Z
-
E
-
Power
-
Block
-
-
~
D board
r-=Gr
-~
0
,...
+
Variable
T2000µF
auto
transformer
-
0
+B MAX CHECK AND CHECK AFTER
IC651
REPLACEMENT
1. Input a monoscope signal.
PICTURE, BRT
Reset
ACpower
130 +
2
v
AC
-0
2. Confirm that 140V line voltage is below 143.04V
DC.
jCHECK
AFTER HVR REPLACEMENT!
1. Tune in an off-air signal.
PICTURE}
BRT
RESET
2. Confirm
the voltage on digital multimeter
is less
than 14.0 ±1.0V DC at TP85.
-28-
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