CTX CMS-3435 - Operational Checks; High Voltage Hold Down Circuit Check

CHECK
OF
HIGH
VOLTAGE
HOLD
DOWN
CIRCUIT
Checking
of
the
high
Voltage
hold
down
circuit
operation.
1. Turn the switch of the unit OFF.
2. Set Brightness, Contrast controls to max.
3.
Connect
a
DC
Voltmeter
and
an
adjustment
jig
as
shown
in
Fig.
2.
4.
Setthe
adjustment
VR
to
fully
counterclockwise.
5.
Turn
the
switch
of
the
unit
ON
and
gradually
rotate
the
adjustment
VR
counterclockwise.
6.
Check
that
a
reading
of
DC
voltmeter
is
less
than
9.4V
+
0.5V
when
picture
disappears.
Clockwise i
Variable
resistor © TPS
To chassis
ground
VR309
500K-B H. V.
1/2
W
Protector
R391 i R390
Main Board Assembly
Fig. 2
7. Turnthe switch of the unit OFF immediately after
checking that the picture disappears.
8. Remove the adjusting jig and the DC voltmeter.
Note: Reading of 9.4V is approximately equivalent
to 28 KV of CRT Anode High Voltage.
PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in the color
monitor units have special safety related charac-
teristics.
These are often not evident from visual inspection nor
can the protection afforded by them necessarily be
obtained by using replacement components rated for
higher voltage, wattage, etc. Replacement parts
which have these special safety characteristics are
identified in this Service Manual.
Electrical components having such features are iden-
tified by marking with "!" on the parts list in this Service
Manual.
The use of a substitute replacement component
which does not have the same safety characteristics
as the manufacturer recommended replacement
one, shown in the parts list in this Service Manual,
may create shock, fire, X-radiation, or other hazards.
Product Safety is continuously under review and new
instructions are issued from time to time. For the
latest information, always consult this Service
Manual.