— 15 —
KV-24FS100/25FS100
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
X
.
+
IABL
ABL
T585
FBT
range
-
amPmeter
3.0 mA DC
A
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:
IC604, 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 <136.6
VDC.
5. If step 4 is not satisfi ed, replace the components listed above, then
repeat Steps 1 – 3.
SECTION 3: SAFETY RELATED ADJUSTMENTS
3-1.
X
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
Y
on the
schematic diagram:
Part Replaced ( )
Adjustment ( )
DY, T585, CRT, IC001, IC561,
C507, C508, C506, T511, L510,
C588, L588, C566, C561, C563,
D567, D568, D566, R567, R568,
R565, R566, R562, R563, R561,
R528....................A Board
HV HOLD-DOWN
R565
PREPARATION BEFORE CONFIRMATION
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 105 VDC.
HOLD-DOWN OPERATION CONFIRMATION
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 138.0 ± 0.3VDC.
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 < 117VDC).
8. Input a white signal and set PICTURE and BRIGHTNESS to
maximum: IABL = 1650 ± 100µA.
9. Repeat steps 4 to 7.
