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A BOARD AND G BOARD
ba R570 CONFIRMATION
METHOD
(HOLD-DOWN
CONFIRMATION) AND READJUSTMENTS
The
following
adjustments
should
always
be per-
formed
when
replacing
the
following
components
(marked with [@ on the schematic diagram).
A BOARD: PM501, Q608, Q607, D531, C545, R570,
R591, R628, R627, T500
G BOARD: 1C653, R675,
2
paasiida before confirmation
1) Turn the POWER
switch ON, and input an
entirely white signals and set the PICTURE
and
BRIGHT controls to maximum.
2) Confirm that voltage of the check terminal of
TP-85 is more than 108V DC when the set is
operating normally with 120.0+2.0V AC supply.
2. Hold-down operation confirmation
1) Turn
the POWER
switch
ON,
and input
an
entirely white signals and adjust ABL current to
1650
+80
pA with PICTURE and BRIGHT etc
controls.
2) Apply DC voltage of over 130V DC gradually to
the check terminal of TP85 via 188119 from the
DC stabilized power source.
Confirm that the minimum
voltage is less than
137.5V DC whereby the raster disappears during
operation of hold-down circuit.
NOTE:
When
the
Hold-down
circuit
starts
operating, switch OFF
the POWER
of
the set immediately.
3) Turn the POWER
switch ON, and receive dot
signals and adjust ABL
current
to 150+50yA
with PICTURE and BRIGHT etc controls.
4) Apply DC voltage of over 130V gradually to the
check terminal of TP85 via 15S119 from the DC
stabilized power source.
Confirm that the minimum voltage is less than
138.5V DC whereby the raster disappears during
operation of hold-down circuit.
NOTE:
When
the
Hold-down
circuit
starts
operating, switch OFF the POWER
of
the set immediately.
3. Hold-down readjustment
When step 2 is not satisfied, readjustment should
be performed by altering the resistance value of
R570 carbon 1/4w (a component marked with B4).
KV-27EXR20/27EXR25
RM-Y104
RM-Y103
G BOARD
B+ VOLTAGE CONFIRMATION
The following adjustments should always be perform-
ed when replacing IC653 and R675.
1) Supply 130H?V AC to with variable autotrans-
former.
2) Input an entirely monoscope signal.
3) Set the PICTURE
control and the BRIGHT
controls in to initial reset.
4) Confirm the voltage of TP91 is less than 137.0V
DC.
5) If step 4) is not satisfied, replace IC653 and R675
repeat above steps.
= fog +
KV-27EXR20/27EXR25
RM-Y104
RM-Y103
digital
multimeter
— 24 —
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