Chapter 12 635
Display/Power Supply Section
Focus Problems
12.Press DISPLAY, MORE 1 OF 2, and FOCUS. While turning the front
panel knob, verify the dc level of the signal at TP9 adjusts about
30 Vp-p.
13.Verify that the front panel intensity adjustment, when used with the
A17R21 Z FOCUS, changes the peak-to-peak voltage at TP9 by 25 V.
Access the intensity adjustment by pressing
DISPLAY, INTENSITY,
and turning the front panel knob.
14.Set front panel intensity to minimum. Set A17R21 Z FOCUS and
A17R26 X FOCUS fully counterclockwise. Verify that the
peak-to-peak voltage at TP9 is about 40 Vp-p (due to X-dynamic
focus circuit).
15.If circuit operation seems correct, the A18V1 CRT is probably at
fault.
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