Sony PVM-9L2 Service Manual page 30

3-3.
Protection
Circuit
Confirmation
3-3-1.
HV
Protector Circuit
Confirmation
1
.
Supply
AC
power
voltage of
1
30
i
?
Vac
to
the unit
and
turn the
POWER
ON.
2.
Input a 480/601
all-black signal
and
set the
BRIGHT
and
CONTRAST
VRs
on
the
User Control screen of
the
menu,
to
MEN.
3.
Check
that
the voltage
between
C1573
positive
terminal
on
D
board and
GND
is
3.80
V
or
more.
4.
Apply
voltage
of 4.6
to 4.8
V
from an
external
DC
power
supply
between
Cl
57
3
positive
terminal
on
the
D
board and
GND.
Confirm
that
the
hold-down
circuit
does
not activate.
5.
Apply
voltage of 4.99
to
5.14
V
from an
external
DC
power
supply
between C1573
positive
terminal
on
the
D
board and
GND.
Confirm
that
the
hold-down
circuit
does not
activate
and
raster
disappears.
3-3-2.
IK Protector
Circuit
Check
1.
Connect an
ammeter and
a variable resistor
10
kQ
between
CN502
pin-7
(ABL)
and
CN1501
pin-6
(OP-
6 V) on
the
D
board.
2.
Adjust
the variable resistor
so that the
value of
the
variable resistor
becomes
maximum
(lOkfi).
3.
Apply
the
130
Vac power
source voltage,
and
turn
on
the power.
4.
Connect
the
480/601
all
black signal to the input
and
adjust the
BRIGHT
and
CONTRAST
of
the
User
Control of the
main
menu
to
MEN.
5.
Adjust
the variable resistor
and confirm
that the
protector circuit
is
activated
and
raster
disappears
at
the
ammeter
value
of 1050
|JA
or lower.
Aside
3-2
PVM-9L2