Check Bandwidth; Check Channel Isolation; Check Common-Mode Rejection Ratio - Tektronix 2205 Service Manual

Adjustment Procedure—2205 Service
f. ADJUST-HF Comp (C241 and R241) for best
flat top on the front corner.
g. Repeat parts e and f until on further improve­
ment is noted.
h. Set the CH 1 VOLTS/DIV switch to 5 mV,
i. Set the generator to produce a 5-division
display.
j. Check for aberrations of 5% (0.3 division) or
less.
k. Repeat part j for each CH 1 VOLTS/DIV switch
settings from 5 mV through 0.5 V. Adjust the gen­
erator output and add or remove the 10X attenuator
as necessary to maintain a 5-division display at
each VOLTS/DIV switch setting.
. Move the cable from the CH 1
l
nector to the CH 2 OR Y input connector. Set the
Vertical MODE switch to CH 2.
m. Repeat part k for Channel 2.
n. Disconnect the test equipment from the
instrument.
NOTE
Install the instrument cabinet for the re­
maining vertical checks
20-minute warm-up period before continuing
with the "Adjustment Procedure". See the
" Cabinet" remove and replace instructions
located in the "Maintenance" section of the
manual.

13. Check Bandwidth

a. Set:
VOLTS/DIV (both)
Vertical MODE
SEC/DIV
Trigger SOURCE
b. Connect the leveled sine-wave generator out­
put via a 5 0 -0 coaxial cable and a 5 0 -0 termination
to the CH 1 X input connector.
or
c. Set the generator to produce a 5 0 -kHz, 6-
division display.
d. Increase the sine-wave frequency until a
4.2-diviston display is obtained.
e. CHECK— the frequency is greater than 20 MHz.
5— 10
DIV switch settings, up to the output-voltage upper
limit of the sine-wave generator being used.
nector to the CH 2
Vertical MODE switch to CH 2.
DIV switch settings, up to the output-voltage upper
limit of the sine-wave generator being used.

14. Check Channel Isolation

X input con­
or
5-division display.
10-division display.
division. :
and allow a
input connector to the CH 1
division.
5 mV
instrument.
CH 1
10 ms

15. Check Common-Mode Rejection Ratio

VERT MODE
put via a 5 0 -0 coaxial cable, a 5 0 -0 termination,
and a dual-input coupler to the CH 1
OR Y input connectors.
f. Repeat parts c through e for all CH 1 VOLTS/
g. Move the cable from the CH 1
input connector. Set the
o r y
h. Repeat parts c through e for all CH 2 VOLTS/
a. Set:
CH 1 VOLTS/DIV
CH 2 VOLTS/DIV
Channel 1 AC-GND-DC
SEC/DIV
b. Set the generator to produce a 20-MHz,
c. Set CH 2 VOLTS/DIV switch to 0.5 V for a
d. Set Vertical MODE switch to CH 1 and ALT.
e. CHECK—The display amplitude is less than 0.1
f. Move the test-signal cable from the CH 2
g- Set:
Vertical MODE
Channel 1 AC-GND-DC
Channel 2 AC-GND-DC
h. CHECK—The display amplitude is less than 0.1
i. Disconnect the test equipment from the
a. Set:
VOLTS/DIV (both)
Channel 2 AC-GND-DC
Vertical MODE
b. Connect the leveled sine-wave generator out­
X input con­
o r
0.5 V
1 V
GND
0.05 ms
OR
X input connector.
OR
CH 2
DC
GND
10 mV
DC
BOTH, NORM.
and ALT
X and CH 2
or
f
i
Y
I