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A
BOARD
R584 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:
IC301,IC521,IC603, DY, D573, D574 C505, C507, C508, C509,
C511, C515, C520, C572, C573, C574, C575, L591, L501,
R582, R583, R585, R586, R578, R579, T504 (FBT)
1.
Preparation before Confirmation
Using Variac, apply AC input voltage: 120+2VAC
1)
Turn the POWER switch ON.
2)
Input a white signal and set the PICTURE and BRIGHT
controls to maximum.
3)
Confirm that the voltage between C574 (+) or TP503 and
ground is more than: 105VDC.
2.
Hold-down Operation Confirmation
1)
Connect the current meter between Pin 11 of the FBT
(T504) and the PCB land where Pin 11 would normally
attach. (see figure 1.0 on next page)
2)
Input a dot signal and set PICTURE and BRIGHTNESS to
minimum: IABL = 100+100µA
Confirm the voltage of A board TP-600 is 135 ± 3VDC
3)
4)
Connect the Digital Voltmeter and the DC power supply
via diode 1SS119 to C574 (+). (See figure 1.0 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
Less than or equal to:
8)
Input a white signal and set PICTURE and BRIGHTNESS
to maximum:
IABL = 1750+100
9)
Repeat steps from (4) to (7).
STANDARD
Less than or equal to:
SECTION 4
SAFETY RELATED ADJUSTMENTS
3.
B+ VOLTAGE CONFIRMATION AND ADJUSTMENT
141.3 VDC
µA
141.3 VDC
— 28 —
KV-29SL40T / 29VL40T / 29XL40T
Hold-down Readjustment
If the current setting indicated in step 2-2 cannot be met,
readjustment should be performed by altering the
resistance value of R584, a component marked with
ammeter
3.0 mA DC
range
ABL
The following adjustments should always be performed
when replacing the following components which are marked
with ] on the schematic diagram:
IC603, IC601, R699
1) Using Variac, apply AC input voltage: 130 + 2.0 VAC.
2) Input a dot signal.
3) Set the PICTURE control and the BRIGHT control to
minimum.
4) Set to service adjustment mode.
5) Select PADJ with
and
6) Adjust with
to the 0 level.
7) Confirm the voltage of A BOARD TP-600 is less than
138 VDC.
8) If step 7 is not satisfied, replace the components, repeat the
above steps.
for: 135 ± 3 VDC
9) Adjust with
and
10) Write into the memory by pressing
.
.
T504
FBT
-
+
A
I ABL
.
then
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