KD-27FS130
KD-27FS130
27
SECTION 3: SAFETY RELATED ADJUSTMENTS
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 R530, R531 component marked with
X
.
3mA DC range
+
-
+
-
A
+
-
FBT
TP85
T503
FBT
TP85
R531 R530
DC Power Supply
digital multimeter
ammeter
Figure 1
3-2. B+ VOLTAGE CONFIRMATION AND
ADJUSTMENT
Always perform the following adjustments when replacing the following
components, which are marked with
Y
on the schematic diagram on the
A Board:
A BOARD
IC600, PH602
Adjustment (
Y
)
1. Using a Variac, apply AC input voltage: 130 + 2.0/-0.0 VAC
2. Input a monoscope signal.
3. Set the PICTURE control and the BRIGHT control to
minimum.
4. Confi rm the voltage on A Board between TP23 and ground is less
than 136.5 VDC.
5. If step 4 is not satisfi ed, replace R530 and R531 on A Board and
repeat the above steps.
3-1.
X
R530, R531 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:
C531, C532, D519, D520,
D521, IC501, IC600, PH602,
R529, R530, R531, R532,
R533, R550, T503 (FBT),
T504 (DFT)
HV HOLD-DOWN
R530, R531
Part Replaced (
Y
)
Adjustment (
X
)
Preparation Before Confi rmation
1. Using a Variac, apply AC input voltage: 120 +/- 2.0 VAC.
2. Turn the POWER switch ON.
3. Input a white signal and set the PICTURE and BRIGHT controls to
maximum.
4. Confi rm that the voltage of more than 23.0 VDC appears between
TP85 and ground on the A Board.
Hold-Down Operation Confi rmation
1. Connect the current meter between Pin 11 of the FBT (T503) and
the PWB land where Pin 11 would normally attach. (See Figure 1).
2. Input a dot signal and set PICTURE and BRIGHTNESS to
minimum: IABL = 2175 + 100/ -325 µA.
3. Confi rm the voltage of A Board TP91 is 134.6 ± 1.0 VDC.
4. Connect the digital voltmeter and the DC power supply to TP85 and
ground. (See Figure 1).
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 = 24.78 + 0.0/ - 0.1 VDC.
8. Input a white signal and set PICTURE and BRIGHTNESS to
maximum: IABL = 2175 + 100/ -325 µA.
9. Repeat steps 4 to 7.
