— 20 —
KV-32V68/35V68
+
-
dejital
multimeter
+
-
A
ammeter
3mA dc range
+
-
dc power supply
11
R530
R531
T503
FBT
TP85
1T40
T503
FBT
TP85
R531
R530
DC Power Supply
digital multimeter
ammeter
3mA DC range
A BOARD:
IC351, IC501, D519, D520, D521, C531,
C532, R387, R529, R530, R531, R532,
R533, R550, T503
G BOARD:
IC643, R661
Step 1
Preparation before Confirmation
Turn the POWER switch ON.
Input a white signal and set the PICTURE and BRIGHT
controls to maximum.
Confirm that, when the set is operating normally, the
voltage at the check terminal of TP85 is more than:
21.5 V DC (KV-32V68)
18.0 V DC (KV35V68)
At AC input: 120.0 ± 2.0 VAC
Step 2
Input a white signal and verify that I ABL is within the
specified range:
2000 + 100
µ
A (KV-32V68),
2160 + 100
µ
A (KV-35V68).
+B = 135.0 + 1.5 VDC .
At AC input: 120.0 ± 2.0 VAC
+
I ABL
ABL
T504
FBT
range
-
ammeter
3.0 mA DC
A
Step 3
Record the voltage between TP85 and ground.
Step 4
Using an external DC power supply, apply voltage
between TP85 and ground.
Increase the voltage gradually and confirm that the
holdown works (raster disappears) at lower than the
voltage recorded in Step 3.
Lower than 26.95 + (-0.05) V DC (KV-32V68),
22.05 + (-0.05) V DC (KV-35V68).
At AC input: 120.0 ± 2.0 VAC
SECTION 4
SAFETY RELATED ADJUSTMENTS
Always perform the following adjustments when replacing the
following components marked with
]
on the schematic diagram:
G BOARD:
IC643, R661
1) Using Variac, apply AC input voltage: 120.0 ± 2.0 VAC
2) Input a monoscope signal.
3) Set the PICTURE control and the BRIGHT control to
initial reset value.
4) Confirm the voltage of G Board CN641 between pin
1
to
ground on "G" PWB is less than 130.0 + 1.0 V DC.
5) If step 4 is not satisfied, replace the R661 and repeat the
above steps.
B+ VOLTAGE CONFIRMATION AND ADJUSTMENT
R530, R531 CONFIRMATION METHOD (HOLD-DOWN CONFIRMATION) AND READJUSTMENTS
A BOARD - CONDUCTOR SIDE
Step 5
Confirm that a voltage appears betwen TP85 and ground,
of more than:
21.5 V DC
(KV-32V68)
18.0 V DC
(KV-35V68)
At AC input: 120.0 ± 2.0 VAC
Always perform the following adjustments when replacing the following
components marked with a
]
mark on the schematic diagram: