SECTION 4
SAFETY RELATED ADJUSTMENT
R568 CONFIRMATION METHOD (HOLD-DOWN
CONFIRMATION) AND READJUSTMENTS
When replacing the following components (marked
with on the schematic diagram) , always perform
the adjustment as follows :
D502, C514, C517, C518, C525,
R512, R521, R522, R555,
T503, DY
(1) Preparation before confirmation
1. Turn the POWER switch ON, and receive entire-
ly dot signals and set the PICTURE and
NESS controls to minimum.
2. Confirm that voltage of T85 is more than
DC when set is operating normally with 120
V AC supply.
(2) Hold-down operation confirmation
1. Turn the POWER switch ON, and receive entire-
ly dot signals and set the
and
NESS controls to minimum.
2. Apply DC voltage to the check terminal of TP85
via
from the DC stabilized power source.
Confirm that the minimum voltage is less than
whereby the raster disappears during of
hold-down circuit.
NOTE
: when the hold-down circuit starts operating,
switch OFF the POWER of the set im-
mediately.
T503
F B T
I
TP85
(3) Hold-down readjustment
When step(2) is not satisfied, readjustment should
be performed by altering the resistance value of R
568 (a component marked with 6).
(4)
of hold-down errorneous operation
the POWER switch ON, and receive dot
signals and set the PICTURE and
controls to minimum.
2. Confirm that the hold-down circuit does not
operate by turning the POWER switch ON and
OFF repeatedly several times.
NOTE
: If the hold-down circuit starts operating in
the above case, switch OFF the POWER of
the set immediately.
3. Turn the POWER switch ON, and receive dot
signals and entirely white signals, and set the
PICTURE and BRIGHTNESS controls to maxi-
mum.
