SECTION 4
SAFETY RELATED ADJUSTMENTS
R530, R531 CONFIRMATION METHOD
Always perform the following adjustments when replacing the following components marked with a ] mark on the schematic diagram:
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 the voltage at the check terminal of TP85 is more than 18.0 V DC when the set is operating normally.
At AC input: 120.0 ± 2.0 VAC
or 220.0 ± 2.0 VAC (for 34SL40C/34VL65C/37VL65C only)
dejital
digitalmultimetermultimeter
+
-
TP85 | T503 |
T503 | |
R53R5131R530 | FBT |
| 11 |
ammetereter
+3mA DCdc rangege
DC Power Supply - | A |
+ 1T40 -
A BOARD - CONDUCTOR SIDE
Step 2
Input a white signal and verify that I ABL is within the specified range: 2160 + 100 μA.
At AC input: 120.0 ± 2.0 VAC
or 220.0 ± 2.0 VAC (for 34SL40C/34VL65C/37VL65C only)
T504
FBT
ammeter
3.0 mA DC range
ABL + A -
I ABL
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 22.05 V DC
At AC input: 120.0 ± 2.0 VAC
or 220.0 ± 2.0 VAC (for 34SL40C/34VL65C/37VL65C only)
Step 5
Confirm that a voltage of more than 18.0 V DC appears between TP85 and ground.
At AC input: 120.0 ± 2.0 VAC
or 220.0 ± 2.0 VAC (for 34SL40C/34VL65C/37VL65C only)
B+ VOLTAGE CONFIRMATION AND ADJUSTMENT
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: 130 + 2.0 VAC
(or 220.0 ± 2.0 VAC for 34SL40C/34VL65C/37VL65C only)
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 is less than 135.5 + 1.0 V DC.
5)If step 4 is not satisfied, replace the R661and repeat the above steps.
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