Safety Related Adjustments; R582 Confirmation Method (Hv Hold-Down Confirmation And Readjustments); B+ Voltage Confirmation And Adjustment - Sony TRINITRON KV-20M42 Service Manual

4-1. R582 CONFIRMATION METHOD
(HV HOLD-DOWN CONFIRMATION)
AND READJUSTMENTS
The following adjustments should always be performed when
replacing the following components which are marked with
on the schematic diagram.
DY, C511, C574, C575, D572, D573, D574, R582,
R583, R584, R585, R586, R578, R625, R626, R634,
R635, T504, IC301, IC521, IC602
Preparation Before Confirmation
1. Turn the POWER switch ON. Input an entirely white
signal and set the PICTURE and BRIGHTNESS controls
to maximum.
2. Confirm that the voltage between C574 (+) and ground
is more than 99.8 VDC when the set is operating normally
with 120.0 ± 2.0 VAC (or 120-220±VAC for
KV-21MB42C/42M/42P/ME42/42C/SB42C/42M/
SE42/42C/82/82C).
Hold-down Operation Confirmation
1. Connect the current meter between Pin 11 of the FBT
(T504) and the PCB land where Pin 11 would normally
attach. (See Figure 1 on the following page.)
2. Input a dot signal and set PICTURE and BRIGHTNESS
to minimum: IABL = 95 + 100/-95
3. Confirm the voltage of A Board TP-600 is
117.0 ± 0.3 VDC.
4. Connect the digital voltmeter and the DC power supply
via diode 1SS119 to C574 (+) and ground
(See Figure 1 on the following page).
5. Increase the DC power voltage gradually until the picture
blanks out.
6. Read the digital voltmeter indication.
7. Turn DC power source off immediately:
(standard: less than or equal to 127.3 VDC).
8. Input a white signal and set PICTURE and BRIGHTNESS
to maximum: (standard: less than or equal to 127.3 VDC).
9. Repeat steps 4 to 7.
KV-20M42/20S42/20S43/21MB42C/21MB42M/21MB42P/21ME42/21ME42C/
SECTION 4

SAFETY RELATED ADJUSTMENTS

A .
m
— 17 —
21SB42C/21SB42M/21SE42/21SE42C/21SE82/21SE82C
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 R582, a component marked
with .
4-2. 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.
IC001, IC602, R030, R626, R632, R633, R635, R636,
R637, R638, R639
1. Supply 120.0 ± 2.0 VAC (or 120-220±VAC for
KV-21MB42C/42M/42P/ME42/42C/SB42C/42M/SE42/
42C/82/82C) to the set with a variable auto transformer.
2. Input a dot signal.
3. Set the PICTURE and BRIGHTNESS controls to minimum.
4. Set to Service Adjustment Mode.
5. Select PADJ with and
6. Adjust with to the 0 level.
7. Confirm the voltage of A board TP-600 is less than
125 VDC.
8. If step 7 is not satisifed, replace the components and repeat
the above steps.
9. Supply 120.0 ± 2.0 VAC (or 120-220±VAC for
KV-21MB42C/42M/42P/ME42/42C/SB42C/42M/SE42/
42C/82/82C) to the set with a variable auto transformer.
10. Adjust with and for 117.0 ± .3 VDC.
11. Press then
T504
FBT
Ammeter
3.0 mA DC
Range
ABL
-
+
A
I ABL
.
to save into the memory.