Adjust Chop Switch B A La N Ce; Check Add Mode O Peration; Adjust High-Frequency Compensation - Tektronix 2205 Service Manual

I. Set the CH 2 VOLTS/DIV switch to 50 mV.
m. Repeat parts d through i except adjust the " 3
and " 3N" trimmers in parts f and i respectively.
n. Set the CH 2 VOLTS/DIV switch to 0.5 V.
o. Repeat parts d through i except adjust the " 4"
arid "4N " trimmers in parts f and i respectively.
p. Set the Vertical MODS switch to CH 1.
q. Repeat parts b through p for the Channel 1
Attenuators.
r. Disconnect the test equipment from the
instrument.
9. Check Vertical ALT Operation
a. Set:
AC-GND-DC (both)
Vertical MODS
SEC/DIV
Trigger SOURCE
b. Position the Channel 1 and Channel 2 traces
about two divisions apart using the CH 1 and CH 2
POSITION controls.
c. CHECK—Channel 1 and Channel 2 traces
move across the screen alternately.
d. Set Vertical switch to CHOP.
e. CHECK—Channel 1 and Channel 2 traces
move across the screen at the same time.
10. Adjust CHOP Switch Balance (R140)
a. Set:
SEC/DIV
Trigger MODE
Trigger SOURCE
b. Connect the 10X probe to the rear of R242 on
top of the A l-M ain circuit board and adjust test
oscilloscope for a 4-division display.
C. ADJUST—Chop-Sw Bal (R140) for no trig­
gering on chop segments when rotating the Trigger
LEVEL control.
11, Check ADD MODE Operation
b. Position both traces on the center horizontal
graticule line using the CH 1 and CH 2 POSITION
controls. '
c. Set the calibration generator to produce a
50-mV signal.
d. Connect the output of the calibration generator
to both the CH 1
with dual-input coupler.
GND
e. Check that both channels show a 2.5-division
BOTH. NORM
display.
and ALT
0.1 s
f. Set: Vertical MODE switch to ADD.
CH 1
g. CHECK—The resultant display is five divisions
3% (4.85 to 5.15 divisions).
h. Disconnect the test equipment from the
instrument.

12. Adjust High-Frequency Compensation

a. Set:
VOLTS/DIV (both)
Vertical MODE
SEC/DIV
b. Connect the positive-going, fast-rise, square-
wave output from the calibration generator via a
5 0 -0 coaxial cable, a 10X attenuator, and a 5 0 -0
termination to the CH 1 OR X input connector.
1 ms
NORM
c. Set the generator to produce a 1-MHz, 5-
VERT MODE
dtvision display.
d. Set the top of the display to the center hori­
zontal graticule Tine using the CH 1 POSITION
control.
e. ADJUST-HF Comp (C242 and C243) for the
5% or less overshoot (0.3 division) on the displayed
signal.
Adjustment Procedure—2205 Service
a. Set:
VOLTS/DIV (both)
AC-GND-DC (both)
Vertical MODE
SEC/DIV
Horizontal MODE
Trigger SOURCE
X input and the CH 2
o r
(C241, C242, C243, and R241)
20 mV
DC
BOTH. NORM,
and ALT
0.5 ms
XI
CH 1
V input
o r
10 mV
C H I
0.2 ms