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PICTURE TUBE REPLACEMENT
Exploded view of optical
assembly.
Replacement of the Picture Tube (CRT) and/or Optical system components of a Projection TV
(PTV) can easily be accomplished by following these general guidelines.
Use care when working around the CRT and optical systems of the PTV. The PTV light path
encompasses a wealth of precision optical components which include lenses, mirrors,
lenticular and Fresnel screens.
The PTV uses three separate CRT's representing the Green, Red and Blue outputs. Each
CRT uses an independent Deflection/Convergence Yoke, Magnetic Centering Ring, coupler,
C-Element lens and Output lens (A/B Lens). Each tube is mechanically fastened to a coupler
that houses fluid (glycol type substance) used to cool the high concentrated temperatures
generated by the small 7 inch CRT's. The fluid also provides an optical characteristic
supporting the optical system of the PTV.
When replacement of a CRT or Optical component is required caution must be exercised in
preventing fluid spillage. The Technician must carefully reassemble CRT/Optical components
insuring a proper seal of the coupling fluid. Use only Factory original coupling fluid.
Note: Do not use or add water as an alternative to the prescribed coupling fluid!
The following procedure should be used when performing repairs on the CRT/Optical
assemblies of the Projection TV:
Note: Upon repair completion of the CRT/Optical assembly, the centering, convergence,
gray scale, mechanical and electrical focus adjustment is required. If more than one
assembly requires repair it is recommended that the Service Technician fully complete
one assembly at a time. Use the existing assemblies as a reference for the alignment of
the centering and convergence.
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