Safety Related Adjustments; R564 Confi Rmation Method (Hv Hold Down Confi Rmation) And Readjustments; B+ Voltage Confi Rmation And Adjustment - Sony KV-25FS12 Manual De Servicio

3-1. X R564 CONFIRMATION METHOD
(HOLD-DOWN CONFIRMATION) AND
READJUSTMENTS
The following adjustments should always be performed when replacing
the following components which are marked with Y on the schematic
diagram:
Part Replaced ( )
DY, T505, CRT, IC501 C507,
C520, C505, C509, C515, T504,
T503, C551, L510, C546, C537,
C547, D517, D518, D519, R560,
R561, R562, R563, R565, R566,
R567, R525....................A Board
IC1301........................MB Board
PREPARATION BEFORE CONFIRMATION
1. Using a Variac, apply AC input voltage: 120-220 ±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 C546 (+) or TP503 and ground is
more than 97 VDC.
HOLD-DOWN OPERATION CONFIRMATION
1. Connect the current meter between Pin 11 of the FBT (T505) 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-600 is 135 ± 1 VDC.
4. Connect the digital voltmeter and the DC power supply via Diode
1SS119 to C546 (+) 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 < 138 ± 0.3 VDC).
8. Input a white signal and set PICTURE and BRIGHTNESS to
maximum: IABL = 1650 ± 100µA.
9. Repeat steps 4 to 7.
SECTION 3: SAFETY RELATED ADJUSTMENTS
Adjustment ( )
HV HOLD-DOWN
R564
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 R564 component marked with X.
3-2. B+ VOLTAGE CONFIRMATION AND
ADJUSTMENT
Note: The following adjustments should always be performed when
replacing the following components, which are marked with Y on the
schematic diagram on the A Board:
A BOARD: IC601, PH601
1. Using a Variac, apply AC input voltage: 130 ± 2 VAC
2. Input a dot signal.
3. Set the PICTURE and the BRIGHTNESS controls to minimum.
4. Confi rm the voltage of A Board TP-600 is <136 VDC.
5. If step 4 is not satisfi ed, replace the components listed above, then
repeat Steps 1 – 3.
— 14 —
KV-25FS12 / 25FS12C
T505
FBT
ammeter
3.0 mA DC
range
ABL
+ -
A
IABL