Section 3: Safety Related Adjustments; R565 Confi Rmation Method (Hv Hold-Down Confi Rmation) And Readjustments; B+ Voltage Confi Rmation And Adjustment - Sony TRINITRON KV-20FS120 Service Manual

3-1. R565 CONFIRMATION METHOD
(HV HOLD-DOWN CONFIRMATION) AND
READJUSTMENTS
The following adjustments should always be performed when replacing
the following components which are marked with
diagram:
Part Replaced (Y)
DY, T585, CRT, IC001, IC561,
IC600, C506, C507, C508, T511,
L510, C588, L588, C566, C561,
C563, D567, D568, D566, PH602,
R567, R568, R565, R566, R562,
R563, R561, R528..........A Board
Preparation Before Confi rmation
1. Using a Variac, apply AC input voltage: 120 ± 2 VAC.
2. Turn the POWER switch ON.
3. Input a white signal and set the PICTURE and BRIGHTNESS
controls to maximum.
4. Confi rm that the voltage between C566 (+) or TP30 and ground
is more than 97 VDC for 20"/21" models, or 105 VDC for 24"/25"
models.
Hold-Down Operation Confi rmation
1. Connect the current meter between Pin 11 of the FBT (T585) and the
PWB land where Pin 11 would normally attach (See Figure 1 on the
next page).
2. Input a dot signal and set PICTURE and BRIGHTNESS to minimum:
IABL = 100 ± 100µA.
3. Confi rm the voltage of A Board TP-23 is 135.6 ± 1VDC.
4. Connect the digital voltmeter and the DC power supply via Diode
1SS119 to C566 (+) and ground (See Figure 1 on next page).
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 < 117.0 VDC) for 20"/21" models
(standard < 138.0 VDC) for 24"/25" models.
8. Input a white signal and set PICTURE and BRIGHTNESS to
maximum: IABL = 1350 ± 100µA for 20"/21" models or
IABL = 1650 ± 100µA for 24"/25" models
9. Repeat steps 4 through 7.
KV-20FS120/21FM120/21FS120/21FA310/24FS120/25FS120

SECTION 3: SAFETY RELATED ADJUSTMENTS

on the schematic
Adjustment (X)
HV HOLD-DOWN
RV565
KV-20FS120/21FM120/21FS120/21FA310/24FS120/25FS120
Hold-Down Readjustment
If the setting indicated in Step 2 of Hold-Down Operation Confi rmation
cannot be met, readjustment should be performed by altering the
resistance value of R565 component marked with
3-2. B+ VOLTAGE CONFIRMATION AND
ADJUSTMENT
Note: The following adjustments should always be performed when
replacing the following components, which are marked with
schematic diagram on the A Board:
A BOARD: IC600, PH602
1. Using a Variac, apply AC input voltage: 130 + 2.0 / - 0.0 VAC.
2. Input a DOT pattern at Q.C.
3. Set the PICTURE and the BRIGHTNESS controls to minimum.
4. Confi rm the voltage of A Board between TP-23 & Ground is =135.6
± 1VDC.
5. If step 4 is not satisfi ed, replace the components listed above, then
repeat steps 1 through 3.
.
T585
FBT
Ammeter
3.0 mA DC
range
ABL
-
+
A
IABL
on the
17