15
KV-21FS105
KV-21FS105
SECTION 3: SAFETY RELATED ADJUSTMENTS
3-1.
X
R562 CONFIRMATION METHOD
(HOLD-DOWN CONFIRMATION) AND
READJUSTMENTS
Always perform the following adjustments when replacing the following
components marked with a
Y
mark on the schematic diagram:
Part Replaced ( )
Adjustment ( )
HV HOLD-DOWN
(R562)
DY, T505, CRT, IC1301, IC501, C507,
C520, C505, C509, C515, T504,
L508, C551, L510, C546, C537,
C547, D517, D518, D519, R560,
R561, R562, R563, R565, R566,
R567, R525........................A Board
Preparation Before Confi rmation
1. Using a Variac, apply AC input voltage: 120-220 +/- 2.0 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 of more than 97 VDC appears between
C546(+) or TP503 and ground on the A Board.
Hold-Down Operation Confi rmation
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 next page).
2. Input a dot signal and set PICTURE and BRIGHTNESS to minimum:
IABL = 100 ± 100 µA.
3. Confi rm the voltage of A Board TP600 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 = 115.7 VDC).
8. Input a white signal and set PICTURE and BRIGHTNESS to
maximum: IABL = 1350 ± 100 µA.
9. Repeat steps 4 to 7.
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 the R562 component marked with
X
.
+
IABL
ABL
T505
FBT
range
-
ammeter
3.0 mA DC
A
3-2. B+ VOLTAGE CONFIRMATION AND
ADJUSTMENTS
Always perform the following adjustments when replacing the 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 ± 2.0 VAC
2. Input a dot signal.
3. Set the PICTURE control and the BRIGHTNESS control to minimum.
4. Confi rm the voltage on A Board between TP-600 and ground is less
than 136 VDC.
5. If step 4 is not satisfi ed, replace the components on A Board listed
above, and then repeat the steps 1-4.
