Philips DPTV305, User Manual

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Note: Upon completion of CRT/optical assembly repair, the centering, convergence, gray scale, mechanical
and electrical focus adjustments are required. If more than one assembly requires repair, it is
recommended the service technician fully complete one assembly at a time, using the existing
assemblies as a reference for the alignment of the centering and convergence.
Disassembly Procedures
A. Removal of a single CRT/Lens Assembly from the light rack
1a) Remove AC power from the PTV.
2a) Remove the upper and lower back covers (1/4" screws).
3a) Remove the barrier board and the shield cover from around the lens assemblies (1/4" screws).
4a) Carefully remove the CRT Socket Board from the CRT of the CRT/optical assembly being serviced.
5a) Remove the yoke and convergence plugs, of the CRT/optical assembly being serviced, from the
Large Signal Module.
6a) Remove the high voltage anode lead from the HV splitter block on the Large Signal Module of the
CRT/optical assembly being serviced. Remove ground lug connectors from the coupler frame.
7a) Remove the four 1/4" screws that secure the CRT/lens assembly to the light rack. These four screws
are located in each corner, on the top of the coupler assembly.
Caution: Do not remove the bolts with pressure springs or the inverted Torx screws of the
CRT/lens assembly. The removal of these components could result in fluid spillage into the
PTV cabinet.
8a) Carefully remove the CRT/lens assembly from the PTV cabinet.
Servicing the CRT/Optical Assembly
Caution: Do not attempt any repairs on the CRT/optical block assembly without first removing the CRT
coupling fluid. Removal of the delta output lens will result in spillage of the coupling fluid.
Caution: Coupling fluid is a poisonous solution containing a high concentration of ethylene glycol. Do
not leave exposed fluid unattended. Prevent children or pets from coming into contact with the fluid.
Clean up spills immediately.
B. Removing the PTV Coupling Fluid
All repairs made to the CRT/optical block assembly require the removal of the coupling fluid. The following
procedure describes how to remove the PTV coupling fluid.
1b) Lay the CRT assembly on its side with the plug pointing up.
2b) Remove the plug (X8).
3b) Remove some of the fluid from the coupler to prevent spillage when the CRT is removed. An empty
coupling fluid bottle with a cone top is recommended to lower the fluid level within the coupler.
Squeeze and hold the bottle and insert the tip of the cap into the drain hole of the coupler. Loosen the
grip on the bottle, allowing the fluid to be pulled up into the bottle. Save the fluid.
4b) Reinstall the plug (X8).
5b) Stand the CRT assembly up with the neck of the CRT pointing up.
6b) With an awl or marking pen, outline the edges of the CRT onto the coupler.
Note: The correct positioning of the CRT to the coupler is critical to the optimum performance of the
optical system.