Focus And Astigmatism Adjustments; Focus Response Adjustment - HP 1317A Operating And Service Manual

Model 1317A
5-74. FOCUS AND ASTIGMATISM ADJUSTMENTS.
WARNING.
Contact with high voltages in this instru-
ment can cause injury or death.
5-75. References. Schematics 7, 8, 9, and 11. Tables
5-1 and 5-2. Figures 5-16, 5-17, and 5-18.
5-76. Procedure.
a. Set BRIGHTNESS for dim spot on CRT.
b. Center spot with POSITION X and POSI-
TION Y.
c. Connect digital voltmeter between
A6RI081
A6R
11
0 junction and ground.
d. Set FOCUS for + 10V reading on digital volt-
meter.
e. Set ASTIG and FOCUS LIMIT A12R6 for
smallest, most round spot.
f. Disconnect digital voltmeter.
g. Set FY1A6R10, FY2A6R11, FX1A6R23,
FX2A6R24, AY1A6R61, AY2A6R62, AX1A6R74,
AX2A6R75, and DRIVE FOCUSING ADJUST A6R43
ccw.
h. Center FOCUS and ASTIG.
i. Adjust F BAL A6R44 and A BAL A6R90 for
best focused spot.
j. Use felt tip pen to mark face of CRT as
shown in figure 5-17.
k. Position spot to point
1.
1. Set FOCUS and ASTIG for smallest, best-
defined spot.
m. Position spot to point 2.
n. Set FXIA6R23 and AX1A6R74 for smallest,
best-defined spot.
o. Repeat steps m and n for each point listed
in table 5-2.
Adjustments
p. Center FOCUS and ASTIG.
q. Connect equipment as shown in figure 5-18.
r. Set pulse generator for positive-going, 0.5
usec wide, 20 kHz, IV p-p output.
s. Adjust F BAL A6R44 to set most negative ex-
cursion, as displayed on monitor oscilloscope, to +5V.
t. Readjust ASTIG and FOCUS LIMIT A12R6
for best-defined spot.
u. Disconnect pulse generator from Z INPUT.
v. Adjust GAIN A6R43 for focused spot.
w. Repeat steps s through v several times;
alternating between bright spot (pulse generator con-
nected to Z INPUT) and dim spot (pulse generator
disconnected) until best compromise between two
conditions is reached.
x. Connect 1kHz sine wave from constant
amplitude signal generator to both X and Y INPUT.
y. Set amplitude to cause a diagonal line display
from corner to corner on CRT.
z. Connect pulse generator to Z INPUT. Note
that pulse (as displayed on monitor oscilloscope)
does not limit at top or bottom.
aa. If limiting occurs in step 3, readjust F BAL
A6R44 until the waveform does not limit; then re-
adjust FOCUS LIMIT A12R6 for best defined spot.
5-77. FOCUS RESPONSE ADJUSTMENT.
5-78. References. Table 5-1, figures 5-16, 5-18,
and schematic 7.
5-79. Procedure.
a. Connect equipment as shown in figure 5-18.
b. Set pulse generator for positive-going, 0.5
usec wide, 20 kHz, IV p-p pulse output.
c. Synchronize monitor oscilloscope to negative-
going edge of pulse.
d. Set HF ADJ NO.1 A5C12 and HF ADJNO. 2
A5R37 for fastest transition with less than 5% over-
shoot.
5-19