Radio Shack TRS-80 Service Manual page 84

SERVICE ADJUSTMENTS
NOTE: Measurements should be made using 12.0 VDC input.
Measurements with kine (CRT) attached will require the
ground strap from kine be connected to chassis to prevent
transistor failures in the event of kine arcing.
FOCUS
Adjust focus control F524 (Figure 1, Zone 2-A) for best
overall focus.
VERTICAL SIZE
Adjust vertiC<lI size control R6t7 (Figure 1, Zone 3-B) to
produce vertical scan of approximately 6 inches.
HORIZONTAL LINEARITY
Loosen deflection yoke clamp and slide linearity sleeve for·
ward or backward to equalize character spacing on left side
of to match character spacing on right side of screen (See
Figure 2 for location of linearity sleeve).
KINE
WIDTH
Note: Check horizontal linearity prior to width adjustment.
Adjust width control to produce horizontal scan 01 approx-
imately 8 inches.
CENTERING
Adjust centering rings on deflection yoke assembly to center
display on screen top to bottom and left to right.
HORIZONTAL HOLD
Horizontal Hold is accomplished by adjustment of the
horizontal oscillator coil (Figure 1. Zone 4·0).
YOKE
CE.NTERING
MAGNETS
Ulrl~~
__
L1NEARITY
SLEEVE
FIGURE 2. DEFLECTION· YOKE ASSEMBLY
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