Safety Related Adjustments; R530, R531 Confirmation Method (Hv Hold-Down Confirmation And Readjustments); B+ Voltage Confirmation And Adjustment - Sony KV-32FV16 Service Manual

KV-32FV16/32FV26/34FV16/34FV16C/34FX260/34FX260C
3-1. R530, R531 CONFIRMATION METHOD
(HOLD-DOWN CONFIRMATION) AND
READJUSTMENTS
Always perform the following adjustments when replacing the
following components marked with a
diagram:
Part Replaced ( )
R387, R550, R529, R530, R531,
R532, R533, D519, D520, D521,
IC501, C531, C532, T503, IC351,
IC355, D302, Q301, R356, R359,
R361, ............................. A Board
IC643, R661 .................. G Board
IC6003,R6008 ............. GA Board
Preparation before Confirmation
1. Using a Variac, apply AC input voltage: 130+2.0/-0.0 VAC.
2. Turn the POWER switch ON.
3. Input a white signal and set the PICTURE and BRIGHT
controls to maximum.
4. Confirm that the voltage of more than 23.0 VDC appears
between TP85 and ground on the A Board.
Hold-Down Operation Confirmation
1. Connect the current meter between Pin 11 of the FBT
(T503) and the PWB land where Pin 11 would normally
attach (See Figure 1 above).
2. Input a dot signal and set PICTURE and BRIGHTNESS
to minimum: IABL = 2175 + 100/ -325 µA.
3. Confirm the voltage of A Board TP91 is 135 ± 1.5 VDC.
4. Connect the digital voltmeter and the DC power supply to
TP85 and ground. (See Figure 1 above).
5. Increase the DC power voltage gradually until the picture
blanks out.
6. Turn DC power source off immediately.
7. Read the digital voltmeter indication
(standard = 27.24 + 0.0/ - 0.1 VDC).
8. Input a white signal and set PICTURE and BRIGHTNESS
to maximum: IABL = 2175 + 100/ -325 µA.
9. Repeat steps 4 to 7.
SECTION 3

SAFETY RELATED ADJUSTMENTS

mark on the schematic
Adjustment ( )
HV HOLD-DOWN
R530, R531
—
14 —
Hold-Down Readjustment
If the setting indicated in Step 2 of Hold-Down Operation
Confirmation cannot be met, readjustment should be performed
by altering the resistance value of R530, R531 component
marked with .
digital multimeter
+
-
TP85
TP85
R531 R530
+
-
DC Power Supply
Figure 1
3-2. B+ VOLTAGE CONFIRMATION AND
ADJUSTMENT
Note: The following adjustments should always be performed
when replacing the following components, which are marked
with on the schematic diagram on the G Board or GA Board.
G BOARD: IC643, R661
GA BOARD: IC6003, R6008
1. Using a Variac, apply AC input voltage: 130 + 2.0/-0.0 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 or GA Board
CN6007 between pin to ground is less than 136.5 VDC.
5. If step 4 is not satisfied, replace the R661 on G Board or
R1008 on GA Board and repeat the above steps.
T503
T503
FBT FBT
11
ammeter
3mA DC range
A
+
-