HP 16500A Service Manual page 47

HP 16500A/16501A - Adjustments
Focus Adjustment
Geometry adjustments must be performed before making the focus adjustment.
1. Remove the rear and side fan. Refer to section 6, "Service," for the fan removal procedures.
2. From the Display Test menu of the Mainframe Test system, select the white cross-hatch test pattern.
3. Adjust FOCUS (RV701), located on the rear PC board, for best overall focus.
Landing and Convergence Adjustment Preparation
1. From the Display Test menu, select a white raster pattern and check for color purity. Repeat this
step using the Red, Green, and Blue raster patterns and check for color purity.
If the color purity is correct, do not perform this Landing and Convergence adjustment.
2. Turn off the instrument, then disconnect the power cord. Loosen the deflection yoke clamp screw.
3. Remove the deflection yoke spacers by moving the deflection yoke towards the rear of the
instrument, then by removing the spacers.
The deflection yoke spacers are tapered rubber blocks located between the front
of the yoke and the rear of the CRT funnel.
4. Plug the power cord into the instrument, then turn on the instrument. For thermal stability, allow the
instrument to warm up for 20 minutes.
Exercise caution when moving purity magnets. Power is applied to the
instrument and high voltages are present around the CRT.
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