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Adjustment Procedure— 2445 Service
DAC REF, CH 1 AND CH 2 INPUT CAPACITANCE,
AND VERTICAL READOUT JITTER ADJUSTMENTS
Equipment Required (see Table 4-1)
Calibration Generator (Item 3)
Digital Multimeter (DMM) (Item 18)
50
Q
BNC Cable (Item 9)
Alignment Tool (Item 19)
50
2
Termination (Item 11)
Normalizer (Item 21)
See
ADJUSTM ENT LOC ATIO NS 3
and
ADJUSTM ENT LO C A TIO N S 4
a t the rear o f this manual for test point and adjustment locations.
Initial Control Settings.
Control settings not listed do not affect the procedure.
VERTICAL VOLTS/DIV
CH 1 and CH 2
0.1 V
CH 1 and CH 2 VAR
In detent
Input Coupling
CH 1 and CH 2
1 MQ DC
VERTICAL MODE
CH 1
On (buttons in)
CH 2, CH 3, and CH 4
Off (buttons out)
ADD, INVERT, and
BW LIMIT
Off (buttons out)
ALT/CHOP
ALT (button out)
VERTICAL POSITION
Midrange
A and B SEC/DIV
0.1 ms (knobs locked)
A and B SEC/DIV VAR
In detent
Horizontal POSITION
Midrange
TRIGGER
MODE
AUTO LVL
SOURCE
VERT
COUPLING
DC
SLOPE
+ (plus)
LEVEL
Midrange
HOLDOFF
In detent
At
On (At readout)
TRACKING/INDEP
INDEP (button out)
INTENSITY
Left of center
READOUT INTENSITY
As required for a visible
display
SCALE ILLUM
Fully CCW
FOCUS
Best focused display
1. Adjust DAC Ref (R2127)
N OTE
The objective o f this step is to make the total range of
the DAC output voltage (sum o f the C C W and C W
readings) equal to 2 .5 V.
a.
Connect the digital multimeter (DMM) negative lead to
the chassis ground. Connect the positive lead to pin 2 of
J118 (on the Main Board).
b. Set the DMM to measure approximately 1.5 Vdc.
c.
Rotate the AREF OR DLY POS control CCW until the
DMM reading remains at a constant value (approximately
— 1.250 V). Note the reading.
d.
Rotate the AREF OR DLY POS control CW until the
DMM reading remains at a constant value (approximately
+1.250 V). Note the reading.
e.
Add the absolute values of the readings noted in parts
c and d together (apprcxima tely 2.500 V).
f.
Subtract the total in part e from 2.500 V, then divide
the difference by two.
g.
ADJUST— DAC Ref (R2127 on the Control Board) to
add the (signed) number obtained in part f to the reading
obtained in part d.
5-7
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 ...
Page 338: ......
Page 346: ...12 2445 SERVICE ...
Page 347: ...2445 SERVICE ...
Page 348: ...2445 SERVICE ...