Quantum Data 801GC, 801GF, 801GX manual Perform the Yoke Winding Orthogonality Check

Outline0 and Outline1 — contd.

Method	Measure the lengths of the two (2) diagonal lines.
	Any difference is an indication of parallelogram
	distortion. The difference in readings should be
	within the specifications of the monitor.
	If the difference in the readings is too far beyond
	spec, the monitor should be rejected and sent back
	for repair before the operator wastes time trying
	to magnet a defective yoke.
Test	Trapezoid distortion correction
Purpose	This image gives you a way to measure trapezoid
	distortion in your monitor. If the distortion isn’t
	too severe, you may be able to correct it by adding
	or adjusting magnets on the yoke.
Method	Perform the Yoke Winding Orthogonality Check and
	Parallelogram Distortion Check tests first to prevent
	an operator from wasting time on a monitor with
	a defective yoke.
	Measure the width of the image at the top and
	bottom of the display. Any difference in readings
	should be within the spec limits. Measure the
	height of the image at both sides of the display.
	Again, any difference in readings should be within
	spec limits. If either of the differences is out of
	spec, the trapezoid distortion of the monitor is
	out of spec.
	Add or adjust magnets on the yoke to correct the
	problem. The Pin & Barrel Correction test should
	be repeated to make sure that it’s still in spec.

4-44 Chapter 4: Built-In Images Model 801GC, 801GF & 801GX¥Rev. X1