— 20 —
KV-34FS12T
SECTION 4
SAFETY RELATED ADJUSTMENTS
4-1.
R564 CONFIRMATION METHOD
(HV HOLD-DOWN CONFIRMATION) AND
READJUSTMENTS
The following adjustments should always be performed when
replacing the following components which are marked with on
the schematic diagram:
Part Replaced (
)
Adjustment (
)
HV HOLD-DOWN
(R564)
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
IC301.............................MA Board
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. Confirm that the voltage between C546 (+) or TP503
and ground is more than 23.0 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 = 2175 + 100/- 325
µ
A.
3. Confirm the voltage of A Board TP-600 is 135 ± 1.5 VDC.
4. Connect the digital voltmeter and the DC power supply
via diode 1SS119 to C546 (+) and ground (See Figure 1
on the 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 < 27.24 + 0.0/- 0.1 VDC) .
8. Input a white signal and set PICTURE and BRIGHTNESS to
maximum: IABL = 2175 + 100/- 325
µ
A .
9. Repeat Steps 4 to 7.
Hold-Down Readjustment
If the setting indicated in Step 2 of Hold-Down Operation
Confirmation cannot be met, readjustment should be performed by
altering the resistance value of R564 component marked with .
+
IABL
ABL
T505
FBT
range
-
ammeter
3.0 mA DC
A
4-2. B+ VOLTAGE CONFIRMATION AND
ADJUSTMENT
Note: The following adjustments should always be performed
when replacing the following components, which are marked with
on the schematic diagram on the A Board.
A BOARD:
IC601, PH601
1. Using a Variac, apply AC input voltage: 130 + 2.0/-0.0 VAC.
2. Input a monoscope pattern.
3. Set the PICTURE and BRIGHTNESS controls to minimum.
4. Confirm that the voltage of A Board TP-600 is <136.5 VDC.
5. If Step 3 is not satisfied, replace the components listed above,
then repeat Steps 1–3.
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