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CRT Set Up
.-----------,
Adhesive
CAUTION: Insure yoke plugs on the A-Board
Focus
-
Electrical Adjustment
are
reconnected before turning the
1.
Cover the Red and Blue CRT, projecting Green
Receiver ON to prevent damage to the
only. The electrical focus controls are located on
horizontal output transistor and/or CRTs.
the front. Adjust the Green Focus VR for best focus
1.
Connect test generator to the antenna terminal and
of overall picture. (Figure 23)
Figure 21. Adhesive Removal
set for a monoscope pattern.
2. Loosen yoke clamp, seat yoke against bell of CRT
.
and rotate to correct yoke tilt (compare to adjacent
CRT). Tighten yoke clamp.
3. Remove adhesive from centering tabs and set
centering tabs for zero correction. (Figure 21)
4. Cover replacement CRT lens and static converge
L
the tubes not replaced, if needed. Check size and
linearity of pattern and adjust as required.
5. Uncover replacement CRT lens and cover other
two CRT lenses. Adjust electrical and optical focus
(lens), if required.
6. Uncover all CRT lenses and use yoke centering
magnet to converge replacement CRT (in center
area of screen only) with other two CRTs.
Disregard non-convergence in areas other than
center area.
7.
Perform White Balance adjustments
-%
0 0 0
R G B
Dynamic Focus Adjustment
1.
Focus adjustments should be performed after 1
hour of aging.
2. Use oscilloscope with 100: 1 probe.
3. Apply monoscope pattern.
4. Adjust the Red, Blue and Green focus VR on the
focus block for best focus of overall picture of each
CRT. (Figure 23)
Figure 22. D. Focus Adjustment Waveform
Figure 23. Focus Pack
2. Repeat for Red focus VR while projecting Red only.
3. Repeat for Blue. (Best focus at bottom left corner
of screen)
Focus
-
Optical Lens Adjustment
Note: This adjustment normally should not require
resetting unless the lens has been replaced or
adjustment has changed.
1.
Optical focus adjustment is located on the top of
each CRT lens system. Loosen the adjustment
knurled locking knob. (Figure 24)
Adjustment knurled
REAR VIEW
Figure 24. Optical Lens focus Adjustment
2. Turn the Receiver ON. Apply and view a
moonscape pattern.
3. Adjust each lens focus for best focus while viewing
each CRT.
4. Cover the Red and Blue CRT, projecting green
only. Rotate the Green lens for best focus around
screen center area.
5. Do the same for the Red focus lens while
projectiug Red only.
6. Repeat for Blue.
5. Connect the scope probe to TPB20, GND to
TPB21. Scope set at 20VIdiv & 5m secldev.
6. Confirm waveform as shown in Figure 22
7.
Proceed with Focus Adjustments.
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