(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
