Ila Bias Settings - JVC 330 Service Manual

Chapter 3---Service Adjustments
8. After Yoke rotation, readjust Geometry, Convergence and CRT
Mechanical focus.
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3.6 ILA Bias Settings
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The ILA Bias settings are factory set and should not normally need adjustment
unless specific maintenance has been performed that requires an ILA
readjustment. Avoid readjusting the ILA
necessary.
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The ILA Bias settings adjust the electrical bias levels to each ILA
"just off" threshold point so that even the smallest incoming light from the CRT
makes the ILA
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ILA assembly at the threshold of operation. If not properly set, image black level
will be adversely affected and the ILA
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light. ILA Bias adjustments should be done in a darkened room.
NOTE: If the room cannot be darkened enough to set the ILA
screen, try holding a piece of paper a few inches from the lens of the color you are
adjusting. Adjust the bias in the usual manner while viewing the entire ILA
assembly area on the paper.
Note On Super Contrast Ila
If using optional Super Contrast ILA
may have to be adjusted for each color prior to performing the ILA
adjustment. This procedure is required whenever an ILA
if the compensator adjustment lever is inadvertently moved.
To set the High Contrast Compensator:
1. Press the HIDE key to mute CRT images.
2. Block the light from the green and blue lenses with the lens caps.
3. Move the front cover forward to provide access to the ILA
4. Disconnect the connector from the top of the red ILA
5. Move the Compensator lever (this lever is just in front of the ILA
connector) to the right and left until the darkest level appears on the
screen. If a screen is not available use a piece of white paper in front of the
lens.
6. Reconnect the connector to the red ILA
7. Repeat the above steps for the green ILA
light from the other two lenses each time.
8. Replace the cover.
9. Remove all lens caps
The CRTs will automatically cut off when you enter the ILA
light on the screen is being reflected by the ILA
To set the ILA
3-8
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assembly react. When properly set, this adjustment will put each
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Assemblies
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Frequency and Bias levels:
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Bias settings unless absolutely
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assembly won't react properly to incoming
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assemblies, the High Contrast Compensator
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.
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and the blue ILA
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assembly.
Model 330, 340SC, 370SC Service Manual
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Bias
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assembly to a
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Biases using the
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bias
assembly is replaced or
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assemblies.
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assembly.
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. Block the
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Bias mode. Any