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A BOARD
CONFIRMATION) AND READJUSTMENTS
The following adjustments should always be per-
formed when replacing the following components
(marked with 0 on the schematic diagram).
1. Preparation before confirmation
1) Remove R651 on the G board and connect a
variable resistor (RVl : about 1OkR ) between
pin @ of IC651 and Bf line.
2) Supply 120+ 2.OV AC to with variable auto-
transformer.
2. Hold-down oneration confirmation
Turn the -POWER switch ON, and input an
entirely white signals and adjust ABL current to
PICTURE and BRIGHT etc controls.
Increase B+ line voltage gradually by adjusting
the resistor of RVl. Confirm that the minimum
voltage is less than 147.OV DC (27 in.) 152.OV
DC (32 in.) 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.
Turn the POWER switch ON, and input a dot
signals and adjust ABL current to 110+30pA
(27 in.) 140f20pA (32 in.) with PICTURE and
BRIGHT etc controls.
Increase B+ line voltage gradually by adjusting
the resistor of RVl. Confirm that the minimum
voltage is lower than 148.5V DC (27 in.) 154.5V
DC (32 in.) whereby the raster disappears during
operation of hold-down circuit.
When the Hold-down circuit starts
NOTE:
operating, switch OF' F ' 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
R565 (a component marked with 8).
R555
SECTION 4
SAFETY RELATED ADJUSTMENTS
METHOD (HOLD-DOWN
-
-
A BOARD
CONFIRMATION)
AND
The following adjustments should always be per-
formed when replacing the following components
(marked with 0 on the schematic diagram).
1. Preparation 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
pin@ of A-O connector is more than 127.OV DC
(27 in.) lOO.OV DC (32 in.) when the set is
operating normally .with 120.0 + 2.OV AC supply.
2. Hold-down operation confirmation
1) Turn the POWER switch ON, and input an
entirely white signals and set the PICIZTRE and
BRIGHT controls to maximum.
2) Apply DC voltage of over 13022.OV DC
gradually to the check terminal of pin @ of A-O
connector via lSS119
power source.
Confirm that the minimum voltage is lower than
the raster disappears during operation of hold-
down circuit.
When the hold-down circuit starts
NOTE :
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
READJUSTMENTS
from the DC stabilized
.
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