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Adjustment Procedure— 2445 Service
2. Check/Adjust CRT Termination (R1501),
Vertical Gain (R638), Vertical Centering (R639),
High-Frequency Trans Resp (C404, R403), Vertical
Readout Jitter (R618), Horizontal Readout Jitter
(R805), and X-Y Phasing (C l 18).
N OTE
If the previous step was not performed, first setup the
Initial Control Settings before the Dynamic Centering
adjustments, then proceed as follows.
C R T
Termination,
High
Frequency
Transient
Response, Vertical Gain, Vertical Centering, and
Readout Jitter adjustments are interactive. This pro
cedure optimizes these adjustments together.
a. Rotate the AREF OR DLY POS control CCW until the
RATIO readout is constant.
N O TE
As a guide when performing the following adjust
ments, optimum performance is achieved when the
CH 1 and CH 2 step response aberrations are
<
4%
when using 10 mV/division deflection factors
0.2
division on a 5-division signal).
i.
ADJUST—CRT Termination (R1501) for best flat-top
approximately 5 ns past the rising edge of the waveform.
The adjustment is accessable through a hole in the top
cover plate. Squeezing the output leads of the termination
inductors (LR1513 and LR1514) toward each other will re
duce the spike that may be present approximately 6 ns be
hind the leading edge.
j.
ADJUST—Trans Resp adjustments (C404 and R403)
alternately for the best flat top on the first 10 ns of the
positive portion of the waveform.
b. Rotate the A control until the readout display indi
cates 130.0%.
c.
CHECK— One cursor is near the bottom horizontal
graticule line and the other is near dotted graticule line
marked 100(%).
d.
Rotate the AREF OR DLY POS control until the read
out displays exactly 100.0%. The cursors should now be on
or near the dotted graticule lines marked 0% and 100(%).
e. Set the CH 1 VOLTS/DIV VAR to the detent position.
N O TE
Care must be taken not to disturb the position o f the
controls adjusted in parts b through e during the bal
ance o f this procedure. If they are accidentally moved,
repeat the procedure from the beginning.
k.
ADJUST—Vertical Gain (R638) and Vertical Center
ing (R639) to vertically center the cursors precisely 5 divi
sions apart (align with the dotted 0% and 100(%) graticule
lines).
I. Press the AV button to turn off the cursors.
m.
Move the test signal to CH 2 and set the VERTICAL
MODE switches to display CH 2.
n.
Repeat part j for CH 2, switching between
CH 1 and CH 2 as necessary, until both CH 2 and CH 1
aberrations are minimized. When minimized, leave CH 2
selected.
o.
Disconnect the Calibration Generator and connect the
Leveled Sine-Wave Generator to the CH 2 input via a BNC
cable.
f. Connect the high-amplitude output of the Calibration
p. Set the generator for a 6-division display at the refer-
Generator to the CH 1 OR X input connector via a 50 S2 BNC
ence frequency,
cable, a Tunnel Diode Pulssr, and a 5X attenuator.
g.
Set the generator Period switch to 100 kHz, and set
the generator amplitude control to maximum.
h.
Rotate the pulser Trigger control CW (from a fully
CCW position) until a stable signal first appears on the grati
cule. Display amplitude will be approximately 5 divisions.
The oscilloscope TRIGGER LEVEL control may need to be
adjusted to obtain a stable display.
q. Change the generator output frequency to 150 MHz.
/
-
'
L
l
a a
i . v /i i L v r \ — L / i o p i a y a m p i i i u u ^ io u c i w c c i i *t.*t u i v o i u i i o
and 5 divisions. This bandwidth provides optimum perfor
mance of the Vertical system.
s.
ADJUST— If necessary, compromise the settings in
part j to obtain the best flat top with the proper bandwidth.
5-17
Summary of Contents for 2445
Page 1: ...Tektronix 2445 OSCILLOSCOPE SERVICE INSTRUCTION MANUAL ...
Page 11: ...2445 Service 3829 01 The 2445 Oscilloscope ...
Page 44: ...Theory of Operation 2445 Service 3831 10A Figure 3 1 Block diagram ...
Page 45: ...Theory of Operation 2445 Service 3831 10B Figure 3 1 Block diagram cont 3 3 ...
Page 210: ...3829 58 Figure 9 4 2445 block diagram ...
Page 214: ......
Page 217: ......
Page 219: ...2445 382 72 ...
Page 222: ...2445 ...
Page 231: ...A 1 t C t t F t G t H t ...
Page 233: ......
Page 236: ......
Page 238: ...2445 392 1 75 ...
Page 244: ......
Page 247: ...A 1 C _____ D E F G H J 2445 3811 74 ...
Page 248: ...1 2 3 4 5 6 7 8 9 i o 2445 DISPLAY SEQUENCER TRIG GERING A4B SWEEPS ...
Page 253: ......
Page 263: ... 0 2445 J8 i S ...
Page 264: ...1 2 3 4 5 6 7 i 8 I i 9 10 2445 READOUT ...
Page 275: ......
Page 278: ......
Page 281: ......
Page 283: ... 8VJNR EG 3S 5 fROM P232 5 10 A 15VUNREG 8S F R O Mn i 2445 3 0 2 S 8 I ...
Page 286: ...2445 3823 82 ...
Page 290: ...B H le w o q 87V T S o I R v n i U1 R1873 PARTIAL A9 HIGH VOLTAGE BOARD 2445 ...
Page 299: ...2445 Service DAC REF A5 CONTROL ADJUSTMENT LOCATIONS 3 ...
Page 300: ......
Page 304: ...2 R E TU R N T O 1 ...
Page 305: ...ERROR MESSAGE DIAGNOSTICS ...
Page 306: ...ERROR MESSAGE DIAGNOSTICS ...
Page 307: ...O A A C t rnra g i tiw c t 3829 89 ...
Page 308: ...RETURN TO ...
Page 309: ...FRONT PANEL TROUBLESHOOTING ...
Page 310: ...FRONT PANEL TROUBLESHOOTING ...
Page 311: ...2445 Service 3829 90 ...
Page 316: ...R E TU R N T O v 1 y ...
Page 317: ...SWEEP TROUBLESHOOTING PROCEDURE ...
Page 323: ......
Page 324: ...2445 Service 3829 85 ...
Page 325: ......
Page 326: ... KERNEL NOP DIAGNOSTIC PROCEDURE ...
Page 327: ...10 POWER SUPPLY TROUBLESHOOTING PROCEDURE 3829 94 ...
Page 330: ......
Page 334: ...2445 Service REGULATOR TROUBLESHOOTING PROCEDURE 3829 93 ...
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Page 346: ...12 2445 SERVICE ...
Page 347: ...2445 SERVICE ...
Page 348: ...2445 SERVICE ...