Philips Colour Television Service Manual page 8

EN 8 4. DPTV585 AA
3. Remove the barrier board and the shield cover from around
the lens assemblies (1/4" screws).
4. Carefully remove the CRT Socket Board from the CRT of
the CRT/optical assembly being serviced.
5. Remove the yoke and convergence plugs, of the CRT/
optical assembly being serviced, from the Large Signal
Module.
6. 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.
7. 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.
8. Carefully remove the CRT/Lens assembly from the PTV
cabinet.
4.3.2 Servicing the CRT/Lens Assembly
Warning: 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.
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.
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.
1. Lay the CRT assembly on its side with the plug pointing up.
2. Remove the plug (X8).
3. 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.
4. Reinstall the plug (X8).
5. Stand the CRT assembly up with the neck of the CRT
pointing up.
6. 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.
7. Remove the four CRT mounting bolts (A) (with springs and
spacers) and remove the mounting bracket (D).
8. Remove the four CRT mounting ear screws.
Note: The CRT mounting ear screws are not used on some
assemblies.
9. Gently remove any metal shavings from around the screw
holes. Do not allow the metal shavings to get into the fluid.
Note the position of the high voltage anode cap with
respect to the coupler.
10. Carefully remove the CRT from the coupler. Wipe any
excess fluid from the faceplate of the CRT. Set the CRT
aside.
11. Use an empty coupling fluid bottle to extract the remainder
of the fluid from the coupler.
Note: Complete removal of the coupling fluid is not
necessary when only replacing the CRT.
12. Clean any remaining fluid from the coupler and the CRT
gasket channel using absorbent tissue. Refer to "C".
Cleaning the Coupler, C-element Lens, and CRT
Faceplate procedure if the fluid is discoloured or
contaminated.
Mechanical Instructions
13. Make all necessary repairs.
C. Cleaning the Coupler, C-Element Lens, and CRT
Faceplate
1. Remove CRT coupling fluid as described in steps B1
through B13.
2. Using denatured alcohol on a cloth made of 100% cotton
or a lens cleaning tissue, gently clean the C-element
(fisheye) lens, coupler and the CRT faceplate. Thoroughly
clean the coupler assembly, including the expansion
chamber bladder, and allow to fully dry.
Caution: Do not use soap or detergent type substances to
clean the coupler and its related assemblies. Water can be
used as an alternative to denatured alcohol, but the
assemblies must be completely dry before reassembly of
the coupler and the addition of the coupling fluid. A hair
dryer may be used to dry the coupler and its assemblies
before reassembly. If contaminated fluid is discovered, the
coupler and its related assemblies must be completely
disassembled and cleaned to prevent a reoccurrence.
3. Replace the CRT and C-element lens gaskets.
4. Reassemble the C-element lens and the output lens to the
coupler.
5. Refer to "Replacing the CRT Coupling Fluid" upon
completion of necessary repairs and cleaning of the
optical/coupler assemblies.
D. Replacement of the CRT
1. Remove CRT coupling fluid as described in steps B1
through B13.
2. Remove the plastic protective coating (if present) from the
faceplate of the replacement CRT.
3. Refer to "Replacing the CRT Coupling Fluid" to complete
the CRT replacement.
E. Repair or Replacement of the Optical/Coupler Assembly
1. Remove CRT coupling fluid as described in steps B1
through B13.
2. Remove the four inverted-type Torx screws, which secure
the Delta output lens to the coupler. An inverted-type Torx
socket can be purchased using part number 4835 395
17303.
3. Removal of the Delta output lens will allow access to the C-
element lens, C-element gasket, coupler, and its
assemblies.
4. Refer to "Replacing the CRT Coupling Fluid" upon
completion of necessary repairs to the optical/coupler
assemblies.
F. Replacing the PTV Coupling Fluid
Notes:
• Before replacing the CRT coupling fluid, ensure the
expansion chamber bladder is fully collapsed. This can be
easily inspected by viewing the bladder through the small
hole on the expansion chamber assembly. If the rubber of
the bladder is not easily visible through the small hole, then
the bladder may be considered collapsed and fluid can be
added. If the rubber of the expansion chamber bladder is
visible at the hole of the expansion chamber, then
replacement of the expansion chamber bladder is required.
• The CRT coupling fluid is critical to the optical performance
of the PTV. Use only part number 4835 310 67032 (3 bottle
kit) or 4835 310 67031 (1 bottle) to ensure the optical
integrity and performance reliability of the PTV when
replacing the CRT coupling fluid.
1. Reinstall the CRT gasket into the gasket channel of the
coupler. Confirm the placement of the CRT, C-element
lens, and vent plug gaskets.
2. Place the CRT onto the coupler with the high voltage
anode lead positioned as marked in step 10 of procedure
B.
3. Carefully position the CRT onto the coupler, using the
outline defined in step 6 of procedure B as a reference.