TM 11-6625-2735-14-1
5. Disconnect the crt base socket from the rear of the
crt.
6. Disconnect the four vertical deflection plate leads
from the Vertical Output board at the crt neck pins.
7. Disconnect the two horizontal deflection plate leads
from the Main Interface board at the crt neck pins
(accessible through an opening at center of the Main
Interface board).
8. Remove the crt bezel and implosion shield.
9. Hold one hand on the crt base and slowly push the
crt forward, guiding the crt face with the other hand. Guide
the anode plug through the crt shield opening while slowly
pulling the crt out of the instrument. The plastic corner-
pads may fall loose when the crt is removed; save them for
reinstallation. Set the crt on a soft material to prevent
scratching.
Cathode-ray Tube Installation
1. Position the crt rear-support (plastic centering
bracket) inside the crt shield approximately 1-1/2-inches
from the rear of the shield.
2. Check that the plastic corner-pads are in place and
seated at the front corners of the crt opening.
3. Insert the crt into the shield. Guide the crt anode
lead through the hole in the shield.
4. Slowly push the crt the rest of the way into the crt
shield. If the crt does not go in all the way, pull it part way
out and find the reason for binding. It maybe necessary to
reposition the rear-support bracket or a plastic corner-pad
for best installation.
5. Clean the crt faceplate, implosion shield and bezel
as directed under Cleaning—Exterior information at the
beginning of this section and install the parts. Lightly
tighten the four bezel screws (approximately 5-inch
pounds).
6. Connect the crt base socket, install the crt rear cover
with two round-head screws and install the blue-plastic
cover on the rear of the instrument with two flat-head
screws.
7. Connect the crt anode lead and carefully connect
the deflection plate leads. After each lead is connected,
lightly pull on the lead to be sure that it will remain in place.
8. 475 DM 43 and DM 40 only–install the DM 43 or DM
40 main circuit-board chassis on the 475 chassis. Install
two screws at the rear of the main circuit-board chassis
and connect three ribbon-cables to the board.
9. If the crt was replaced, part of the 475 calibration will
need to be checked or adjusted. See Table 4-5 under
Recalibration After Repair (later in this section) for a
listing of calibration checks and adjustments that need to
be checked after crt replacement.
High-Voltage Multiplier Removal
1. Remove the Vertical Preamp circuit-board as outlin-
ed previously.
2. Remove the cathode-ray tube as outlined previous-
ly.
3. Remove the high-voltage shield from the Main
Interface circuit-board and remove one screw near the
INTENSITY potentiometer.
4. Remove four hexagonal posts, used to mount the
high-voltage shield, from the Main Interface board with a
3/16-inch nut-driver.
5. Remove the two nylon nuts from the Main Interface
board near C1328.
6. Remove three screws holding the multiplier shield
to the main chassis and remove the shield.
7. Unsolder the black wire from the Multiplier at the
Main Interface board.
8. Unsolder one wire from a post on the High-Voltage
Multiplier.
9. Unsolder the flexible grounding-braid from the case
of integrated circuit U470 (on the Vertical Output board),
using a 40 to 60-Watt soldering iron.
10. Remove one screw that holds the crt neck shield to
the black-plastic rear bracket.
4-31
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