Tektronix 371B, Service Manual

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Performance Verification
371B Service Manual
5-33
5. ADJUST SY POSITION adjustment R528 and SX POSITION adjustment
R508 on the A5 Display Control board so that the center cross mark of the
frame test pattern conforms to the center dot of the dot pattern (not the center
of the graticule).
Examining and Adjusting DIA Gain.
6. EXAMINE the display to determine whether the outer eight dots of the dot
pattern are located between the inner frame and outer frame of the frame test
pattern.
If the location is not correct, the following adjustment is necessary.
7. ADJUST D/A GAIN adjustment R842 on the A4 Digital Display board to
position the outer eight dots between the inner frame and outer frame of the
frame test pattern.
D/A Gain adjusts the size of the frame test pattern without changing the dot
test pattern size.
Checking and Adjusting the Display.
The dot frame test patterns are visual aids for
display alignment. Positioning, straightening and sizing of the display involves
several adjustments. Three of these adjustments, GEOMETRY, TRACE
ROTATION, and ORTHOGONALITY, are interactive.
GEOMETRY adjusts the curvature of the sides, top and bottom of the test
pattern.
TRACE ROTATION tilts the test pattern about a pivot point approximately
2.5 divisions from the right side of the graticule on the horizontal line.
ORTHOGONALITY changes the test pattern shape from the rhombus to
rectangular.
X-GAIN and Y-GAIN change the test pattern from rectangular to square.
Front-panel POSITION controls change the position of the whole display.
Checking Orthogonality.
8. Change the following 371B settings: