Tektronix 2465A Service Manual page 152

Adjustment Procedure-2465A/2467 Service
t. CHECK-Display amplitude is between 4.4 divisions
and 5 divisions while the generator frequency is changed
from 350 MHz to 250 MHz. This bandwidth provides
optimum performance of the Vertical system.
u. CHECK-Display amplitude does not drop below 4.4
divisions when sweeping the generator frequency from
250 MHz to 350 MHz.
v. ADJUST-HF Adjust (R417) if necessary to meet the
criteria given in steps t and u.
w. Press and release the upper TRIGGER COUPLING
switch.
x.
Check-Readout indicates ADJ
A
(step) 2, 10 mV,
10 ns.
y. Connect the high amplitude generator, Tunnel Diode
Pulser, 5X attenuator combination to CH 1 OR X input via
a 50
n
BNC cable.
z. ADJUST - Trans Resp adjustments (R411, C403,
L403) and the A control for best response.
aa. Disconnect the Tunnel Diode pulser and connect
the fast rise output of the Calibration Generator to CH 1
OR X via a 5X attenuator and a 50
n
BNC cable. Note the
amount of roll up or roll down in the first 3 ns. This
difference represents the error between the Tunnel Diode
pulser and the high amplitude generator.
bb. Press and release the upper TRIGGER COUPLING
switch (step 3). Move the test signal to CH 2 and
ADJUST amplitude for 5 division signal.
cc. ADJUST -A until CH 2 waveform matches that
noted in step aa above.
dd. Press and release the upper TRIGGER COUPLING
switch (step 4). Connect the test signal to CH 1 through
2X, 2.5X, and 5X attenuators. ADJUST A for best front
corner.
ee. Press and release the upper TRIGGER COUPLING
switch (step 5). Remove 2.5X attenuator. ADJUST A for
best corner.
5-22
ff. Press and release the upper TRIGGER COUPLING
switch (step 6). Remove 5X attenuator. ADJUST genera-
tor for a 5 division signal. ADJUST A for same corner
noted in step ee above.
gg. Press and release the upper TRIGGER COUPLING
switch (step 7). Adjust generator for 5 division signal.
ADJUST
A
for best corner.
hh. Press and release the upper TRIGGER COUPLING
switch (step 8). Adjust high amplitude generator for 5 divi-
sion signal. ADJUST
A
for a spike on the corner of 4 to
5%. This is necessary to have the 1 OX bandwidth (.1 V -
.5 V) to be similar to the 10 mV bandwidth.
NOTE
Generator amplitude for the 500 m V step will be
approximately 2 divisions and the amplitude for the
1 V step will be approximately 1 division.
ii. Remove 2X attenuator. Continue through step 11 as
above.
jj. Press and release the upper TRIGGER COUPLING
switch. Steps 12 and 13 are automatically calibrated. Con-
nect test signal to CH 2 via 2X, 2.5X, and 5X attenuators
and adjust for 5 division signal. ADJUST A for best corner.
kk. Repeat steps dd through ii for CH 2 (steps 14-21 ).
II. Steps 22 and 23 are automatically calibrated after
step 21.
mm. CHECK-Readout indicates VERT CENTER and
GAIN.
nn. ADJUST -Gain (R638) for precisely 5 divisions
between the two horizontal cursors.
oo. ADJUST -Vertical Centering (R639) to center the
cursors on the graticule (align the cursors with the dotted
0% and 100% graticule lines).
pp. Press and release the upper TRIGGER COUPLING
switch,
qq. Disconnect the test setup.