Check/Adjust High-Frequency Compensation; Selected Components - Tektronix 453 Instruction Manual

Performance Check/Calibration-Type 453/R453
TABLE 5-4
Range of Values (to Conditions for select-
Selection procedure
provide a 2 to 3%
Device(s)
for which ing ( 20 mV /DIV, four-
Selected
total compensating ef- this provides a com- division 100 kHz sig-
Component feet)
pen sating effect nal applied)
l. C38 .001 to .Ol µF
Q23, Q33 MODE CH l
Select for best flat top
lO µs/DIV
over first 2 to 5 micro-
MAG OFF seconds
2. C264 14 to 47 pF Delay line MODE CH l Select for best flat top
2 µs/DIV over first 0.2 to 0.6 micro -
MAG OFF
seconds
3. Cl38
.001 to .01 µF Ql23, Ql33 MODE CH 2
Select for best flat top
lO µs/DIV over first 2 to 5 micro-
MAG OFF seconds
4. Rl95
24 k to 300 kn
Q84, Q94, Ql 84, Ql 94
MODE CH 2
Select for best match of
24. Check/ Adiust High-Frequency
Compensation
@
SELECTED COMPONENTS
The Vertical Preamp circuit board has four selected
components which provide high-frequency com-
pensation for various devices within the Vertical
Deflection System. It should not be necessary to
re-select these components unless the devices for
which they compensate have been changed. Use
Table 5-4 to select these components. If more
than one component needs to be selected, select
the components in the order given in this table.
All of the selected components except Rl 95 are
mounted in sockets in the circuit board to facili-
tate selection. The location of each selected com-
ponent is shown on Fig. 5-17. Table 5-4 lists the
range of component values which provide cor-
rect compensation.
C38 and C 138 are selected from among the fol-
lowing capacitors.
. 001 µ,F
283-0067-00 200
v
±10%
.0015 283-0114-00 200
v
±20%
.0022 283-0119-00 200V
±5%
.0027
283-0142-00 200
v
±5%
.0033 283-0041-00 500
v
±5%
.0047 283-0083-00 500
v
±5%
.01
283-0079-00 250
v
±20%
C264 is selected from among the following capaci-
tors.
14 pf 281-0577-00 500
v
I
±5%
18 pf 281-0578-00 500
v
±5%
22 pf 281-0511-00 500
v
±2.2 pf
27 pf 281-0512-00 500
v
± 2.7 pf
33 pf 281-0629-00 600
v
±5%
39 pf 281-0603-00
500
v
±5%
47 pf 281-0519-00 500
v
±4.7 pf
0
2 µs/DIV
Channel 2 to Channel l
MAG OFF over first 0.5
ond
a. Change the following control settings:
VOLTS/DIV (CH l and 2)
MODE
20mV
CH l
A and 8 TIME/DIV .5 µs
microsec-
b. Connect the square-wave generator fast-rise.
+
output
to the Channel l INPUT connector through the five-nano-
second GR cable, 5X GR attenuator and 50-ohm in-line
termination, in given order.
c. Set the square-wave generator for fast-rise operation
and four-division display at l 00 kilohertz.
d. CHECK-CRT display for optimum flat top (see Fig.
5-17A).
e. ADJUST-C263 and C265 (see Fig. 5-17C) for optimum
flat top.
f. Change the following control settings:
A and 8 TIME/DIV .2 µs
MAG XlO
g. CHECK-CRT display for optimum square corner and
flat top (see Fig. 5-178) .
NOTE
In the following steps, change the MAG switch
from X 10 to OFF and compare the response at
both sweep rates. Then adjust for the best overall
response.
h. ADJUST-R49, C49, R328, C336, C328, C54, and C45A,
in given order, (see Fig. 5-17C and D) for optimum square
corner and flat top. Repeat this adjustment until optimum
high-frequency response is obtained (similar to Fig. 5-178).
i. Set the MODE switch to CH 2.
j. Disconnect the 50-ohm in-line termination from the
Channel 1 INPUT connector and connect it to the Channel 2
INPUT connector.
5-19