Tektronix 2445, Instruction Manual

Page: 136 / 351

Adjustment Procedure— 2445 Service
t. Move the input signal to CH 1 and select CH 1 for
display.
3. Set CH 1 and CH 2 DC Balance.
NOTE
u. Repeat parts p through s for CH 1. If readjustment of
C404 or R403 is necessary, repeat parts j through s.
The instrument must have had a 20-minute warmup
prior to performing the next step to ensure accuracy.
v. Set the A and B SEC/DIV switch to 1 ms.
a. Set:
w. Select CH 1 for display.
Input Coupling
CH 1 and CH 2 IMS) AC
x. Press and release the AV button to obtain a AV
display.
b. Press up momentarily and release the CH 1 and CH 2
Input Coupling switches simultaneously.
y. Use the AREF OR DLY POS control to position one
cursor 3 divisions above graticule center and use the A con­
trol to position the other cursor 3 divisions below graticule
center.
c. CHECK— A moving dot display replaces the normal
display for approximately 10 seconds, then the display re­
turns to normal.
z. Connect a 1 kHz, fast-rise signal from the Calibration
Generator to the CH 1 OR X input connector via a 50 Q BNC
cable.
d. CHECK— For less than 0.2-division vertical trace shift
when the CH 1 VOLTS/DIV switch is rotated through all of
its settings.
aa. Set the generator output level for an 8-division
display.
e. Set the VERTICAL MODE switches to disable CH 1
and display CH 2.
bb. Use the CH 1 Vertical and the Horizontal POSITION
controls to center the CH 1 display on the graticule.
f. CHECK— For less than 0.2-division vertical trace shift
when the CH 2 VOLTS/DIV switch is rotated through all of
its settings.
cc. ADJUST—Vertical Readout Jitter (R618) for mini­
mum vertical jitter of the readout characters and cursors.
4. Adjust X-Y Phasing (C l 18).
a. Set:
dd. Press the At button to obtain a At cursor display.
VOLTS/DIV
CH 1 50 mV
Input Coupling 50
Q
DC
ee. Using the AREF OR DLY POS and A controls, posi­
tion the cursors to the 2nd and 10th graticule lines.
A SEC/DIV X-Y
VERTICAL MODE
CH 1 On (button in)
CH 2 Off (button out)
ff. Press the X I0 MAG button to magnify the display.
gg. ADJUST— Horizontal Readout Jitter (R805) for mini­
mum horizontal jitter of the readout characters and cursors.
b. Connect the Primary Leveled Sine-Wave Generator to
the CH 1 OR X input connector via a 50
Q
BNC cable.
hh. Disconnect the test setup.
c. Set the generator frequence to 1 MHz and adjust the
amplitude for a 6-division vertical signal display.
5-18