4)
Check
that
the
HV
HOLD
DOWN
circuit operates
normally
if
the following parts are replaced:
(Marked
*)
DD
board
or
a
part
on
it.
DE board
or
a part on it.
D board
or
Q309 on it.
Checking Method
Apply 9.7 VDC
or
less between pin ®
of
con-
nector
D-3
on
D board and the ground from the
outside and check
that
the HOLD
DOWN
circuit
operates and the raster disappears.
5)
Check
that
the beam protector
(1)
operates normally
if the following parts are replaced:
(Marked
*)
DD board or a
part
on
it.
D board
or
R332 on it.
Checking Method
(Adjust the voltage
on
TP304
to
9.00 iO.OS VDC
by rotating RV301 before checking.)
The raster should show
if
between pin ® on
the
DE board and ground is shorted and power is
turned on.
2 When a variable resistor of over 12
kn
is con-
nected in series with an ammeter between TP303
and ground and the resistance value is gradually
reduced form
it's
maximum value, the
protector
circuit shall function and the rasters disappear
when the currect value drops below 1.13 rnA.
3 Removal a short clip between pin
® on the DE
board and ground.
6)
Check
that
the beam
protector
(2)
operates normally
if
the
following parts are replaced:
(Marked
*)
DD board
or
a parts
on
it.
DE board
or
a parts
on
it.
D board
or
Q309
on
it.
Checking Method
I The raster should show
if
between TP306 and
ground
is
shorted and power
is
turned on.
2' When a variable resistor of over 12
kn
is con-
nected in series with an ammeter between TP303
and ground and the resistance value is gradually
reduced form
it's
maximum value,
the
protector
circuit shall function and the rasters disappear
when the currect value drops below 1.16 rnA.
3 Removal a short clip between TP306 and ground.
4-10
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