Section IV. CORRECTIVE MAINTENANCE
Warning: A high voltage exists at the anode of the CRT.
Deenergize the equipment before proceeding with
replacement of the CRT.
This section contains typical parts removal and replacement instructions that are within the scope of maintenance
Caution: Handle the CRT with great care to prevent breakage.
5-11. Removal of the Main Frame and Plug-In Assemblies (Fig. 5-14)
(1) Disconnect the tube socket (1) from the base of the CRT.
(2) Disconnect the high-voltage cap (2) from the high-voltage anode connector on the CRT.
Remove and install the carrying case and plug-in assemblies.
(3) Disconnect the four leads (3) from the pins (4) that protrude from the neck of the CRT.
Note. When replacing the plug-in assembly, make sure the plug-in assembly connector guide pin is alined with
Note. Before disconnecting the leads, record their colors and the lugs to which they are connected.
the main frame connector guide hole.
(4) Disconnect the ground lead (5) from the CRT shield (6).
(5) Remove the four ring knobs and rubber washers (7 and 8) that fasten the ring front and graticule scale (9 and 10)
(6) Remove the ring front and graticule scale.
(7) Loosen the clamp (11) at the neck of the CRT.
(8) Remove the CRT by slowly pulling it out of the CRT shield and through the opening in the front panel.
Caution: Be careful not to damage the four pins that protrude from the neck of the CRT.
(1) Insert the CRT through the opening in the front panel and into the CRT shield, making sure the CRT high-voltage
anode connector is on the same side as the high-voltage cap.
(2) Connect the tube socket, high-voltage cap, ground lead, and the four leads to their proper locations.
(3) Tighten the clamp at the neck of the CRT.
(4) Install the graticule scale and ring front.
Note. After the tube is installed, it may be necessary to aline the trace to the graticule scale.
Figure 5-15. Replacement of the CRT.
Figure 5-14. Removal and installation of the main frame and plug-in assemblies.