HP 8568B manual CRT Cut-Off Voltage

2.High-Voltage Adjustment (SN 3001A and Below)

34.On the oscilloscope, adjust the channel 1 offset voltage as necessary to measure the peak-to-peak CRT cut-off voltage, V,,, at AlA3TP5. See Figure 3-9. This peak-to-peak voltage should be between 45-75 V,.,. Note this voltage for use in step 39.

1 1 0 . 0 V/div offset: 6 0 . 0 0 v

10.00 : 1 dc

- 2 5 0 . 0 0 0 us	0 . 0 0 0 0 0 s	2 5 0 . 0 0 0 us
	5 0 . 0 us/dlv

1 f 7 5 . 0 0 v

Figure 3-9. CRT Cut-Off Voltage

35.Connect a separate function generator to each of the X and Y inputs of the Display Adjustment Board, as shown in Figure 3-5. Set the function generators as follows:

X input Jl:		. . . . . . . . .. . . . . . . . .500 kHz
frequency
w a v e .	.
amplitude
Y input 52:		.	. . . . . . . . . . 1 kHz
frequency
w a v e .		. .	. . . . . .
amplitude

36.Adjust AlA2R35 INT LIMIT clockwise until the display is just visible.

37.Adjust AlA4R7 POS, AlA5R7 POS, and if necessary the function generator de offsets for a full-screen illumination.

38.Set the front-panel INTENSITY control fully counter-clockwise, and, if it is not sealed, adjust AlA2R5 INT GAIN fully clockwise. Adjust AlA2R35 INT LIMIT just below the threshold at which the display illumination becomes visible.

Adjustments 3 - 35