(Press USER DEFINABLE KEY #5 to start the sequence
and BREAK to stop the sequence.)
Calibration—492/492P Service Vol. 1 (SN B030000 & up)
Adjustment Procedure
d. Adjust Rne Tune Range, R4040, until the displayed
signals for alternate sweeps align horizontally with those on
the initial sweep.
e. Adjust the 2nd LO Tune Sensitivity as follows:
1) Apply 0.5 ms markers to the RF INPUT, change the
FREQ SPAN/DIV to 1 MHz, and tune FREQUENCY
to about 0 MHz. Decrease the FREQ SPAN/DIV to
5 kHz and tune the zero spur to the left side of the
display. Decrease the FREQ SPAN/DIV to 500 Hz.
2) Send: “TUNE 2K;SIG;WAIT;TUNE -2K;SIG; WAIT;
REP 150”. This will repeat the adjustment sequence
for five minutes. Repeat the command if necessary.
(Press USER DEFINABLE KEY # 6 to start the sequence
and press BREAK to stop the sequence.)
3) Adjust Fine Tune Sensitivity R3040 until the
harmonics displayed in alternate sweep have the
same horizontal location as the even sweep. Note:
This may take some time because of the long sweep
time and drift.
PROGRAM TO FACILITATE CALIBRATING THE 1st LO DRIVER AND THE CENTER FREQUENCY CONTROL
BOARDS OF THE 492P, USING TEKTRONIX 4050-SERIES COMPUTER TERMINAL
1 ON SRQ THEN 700
2 GO TO 700
4 ON SRQ THEN 100
5 GO TO 210
8 ON SRQ THEN 100
9 GO TO 230
12 ON SRQ THEN 100
13 GO TO 300
16 ON SRQ THEN 100
17 GO TO 400
20 ON SRQ THEN 100
21 GO TO 500
24 ON SRQ THEN 100
25 GO TO 600
100 REM *** ERROR HANDLING ROUTINE ***
110 POLL Z8,Z9;A9
120 PRINT @A9:“ERR?’
130 INPUT @A9:Z$
140 PRINT @Z$
150 RETURN
200 REM *** ADJUST COARSE TUNE RANGE R1032 CEN FRE CONTROL BRD
210 PRINT @A9:“FRE 0'
220 RETURN
230 PRINT @A9:“FRE 4278M"
240 RETURN
300 REM *** ADJUST 1 ST LO SENSE (GAIN) AND OFFSET ***
310 PRINT @A9:“FRE 100M;DEG;SIG;WAI’
320 PRINT @A9:“FRE 1.8 G;DEG;SIG;WAI’
330 GO TO 310
400 REM *** ADJUST COARSE TUNE SENSITIVITY R1028 CEN FRE CON BRD
***
3-56
REV FEB 1983
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