Hitachi 46W500 Training page 151

DP-3X THINGS YOUR SHOULD KNOW
(19)
Using the Cutoff Adjustment to check for a bad CRT.
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Symptoms:
•
Color Temperature changes.
•
Picture Flickers.
•
Brightness fluctuations.
Did you know that you can check for a defective CRT (internal grid shortage) by looking closely at
the single horizontal line while in the Cut-Off adjustment mode?
In this mode, the Vertical is collapsed so the Service Technician can adjust the Cut-Off level of
each CRT. (Note: This determines the Life Span of the CRT. If this adjustment is too bright, the
Tube Life is shortened).
PROCEDURE:
2
Enter the I C Service Menu and Select the SERVICE adjustment by using the cursor down and
then press cursor right. Vertical will collapse.
•
(See CutOff adjustment procedure
While looking at the single colored line, look at any color to see if it's blinking or flickering. If it
is, the CRT needs to be replaced. The Room should almost dark to make the line easier to
see. You may have to turn the Screens up slightly to see the line more clearly. Remember,
the line should be just barely visible.
If a Color can't be turned completely off, this too indicates a defective CRT and can quickly
identify when CRT is bad.
Replace the defective CRT.
(Note: This isn't related to the Digital Convergence Grid. The Cursor (adjustment point) will blink in
this mode and this is normal).
(20) Some VGA to Component Adaptors can cause No Picture or Sync Problems.
•
Some Set Top Boxes do not have Component Outputs. They have VGA outputs. In this case,
a VGA to Component adaptor will be needed. Some of these adaptors can cause a problem if
they do not have Tri-Level sync outputs.
•
They may cause other problems as well, like Horizontal Shift or unstable pictures.
•
Please remove the VGA to Component adaptor and test the Component inputs by using a
Component generator directly into the Component inputs to verify.
•
Please see the VGA to Component adaptor recommendations on the HD Generator sugges-
tion page.
Note: If a Component Source isn't readily available, use Composite Video input into
the "Y" jack. Insert a dummy RCA jack into the "Pr" plug to force the set into the Com-
ponent Mode.
The signal will be black and white, but the picture content (other than color problems)
can be checked.
(Also Item 14 see Spark Gap problems)
in DP-2X Web).
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