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21. Loosen yoke and shield retaining clamp and carefully
slide assembly off CRT neck.
22. Install yoke and shield assembly on new CRT in
location noted in step 20.
23. Install new CRT in reverse order, ensuring that CRT
grounding spring (step 14) and yoke shield ground
wire(s) (step 12) are reconnected.
24. Perform all Model 2 display station image adjustments
(5.2.1 through 5.2.1.7).
5.3.3.2 Yoke and Shields
The yoke and shield assemblies are removed from the CRT
neck
as
a unit. After the assemblies are removed, they can
be
separated.
Note: Top cover on Model 2 display station must be
removed before cone sh ield can be moved back to observe
CRT filament.
1. Disconnect yoke cable from analog card, and disconnect
ground wire(s) from yoke shield.
2. Remove socket from base of CRT. (On Model 1 display
stations it is necessary to perform step 3 before socket
can be removed.)
3. Remove cone shield from base area of CRT:
a. Loosen shield retaining shoulder screw.
b. Rotate cone counterclockwise until locking tabs
disengage.
c. Pull cone straight back and clear of CRT neck.
4. Note approximate orientation of yoke with reference to
CRT.
5. Loosen yoke and shield retaining clamp and carefully
slide assembly off CRT neck.
6. Separate yoke from shield.
7. Replace in reverse order. Position yoke on CRT as noted
in step 4. (Yoke cable should be at bottom, and clamp
screw shouid be on left side as viewed from top·front of
display station.)
8. Ensure that grounding spring (fingers) on front of yoke
is in contact with the conductive coating of the CRT bell
by pressing yoke assembly toward face of CRT before
tightening clamp screw.
9. Perform all display image adjustments (5.2.1.4 through
5.2.1.7).
5.3.3.3
Modell Analog Card
CAUTION
Perform HV power supply check (par. 5.1.3.5) before
installing a new analog card. Premature failure of new
analog card may result if power supply is defective.
1. Unplug connectors at top of analog card.
2. Loosen the two captive screws passing through analog
card and into wire form. (These two screws have large
knurled heads and a spacer on them.)
3. UnpJug bottom connector.
4. Remove analog card from machine.
5. Remove the two screws and spacers from old analog
card.
6. Reassemble screws and spacers in new analog card.
7. Plug in bottom connector.
8. Replace analog card in machine.
Note: The two open slots in the rear edge of the analog
card must fit into the slots in the rear leg of the wire
form.
9. Tighten the two captive screws.
10. Plug in two top connectors.
11. Perform analog card adjustments (paragraphs 5.2.1.6
and 5.2.1.7) if a new card is installed or if the
adjustments were disturbed.
5.3.3.4 Model
2
Analog Card
CAUTION
Perform HV power supply check (par. 5.1.3.5) before
installing a new analog card. Premature failure
o'f ;:
a'b
analog card may result if power supply is defective.
1. Open logic gate.
2. Remove the two upper screws supporting analog card
shield, and lift off shield.
3. Unplug cables plugged into front of analog card.
4. Remove the two screws holding analog card to base
chassis.
5. Remove analog card from support.
6. Unplug rear connector.
7. Replace in reverse order.
8. Perform analog card adjustments (paragraph 5.2.1.7) if a
new card is installed or if the adjustments are disturbed.
5.3.3.5 Modell Brightness and Contrast Controis
The Brightness and Contrast controls are part
ot
the prime
power box on Model 1 display stations. Do not replace
these controls; replace prime power box. See paragraph
5.3.2.4 for prime power box replacement procedure.
5.3.3.6
Model
2
Brightness and Contrast Controls
1. Unsolder the three leads on each of the two poten-
tiometers. Note terminals from which wires are removed,
for later reinstallation.
2. Pull the two knobs off concentric control shafts.
3. Remove rear-most C clip on slider bracket that retains
slider bracket to potentiometer shaft.
4. Pull off large retaining clip that holds potentiometers to
mounting bracket.
5. Lift assembly clear of unit from rear.
Checks, Adjustments, and Removals
5-13
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