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MODEL
8559A
ADJUSTMENTS
ADJUSTMENTS
5
-
17. POWER SUPPLY CHECKS AND ADJUSTMENTS (Cont'd)
NOTE
The two following voltage adjustments,
+
10V
and VO (Varactor Offset),
must be performed while the spectrum analyzer is still cold (during first five
minutes after turn
-
on). If the instrument has been operating longer than five
minutes, turn off the display mainframe, remove A8 and A9 assemblies, and
let them cool on bench for 15 minutes. Replace the two assemblies and
proceed with adjustment of
A9R2 and A8R62 during the first five minutes
after turn
-
on.
7.
Connect digital voltmeter to
+
10V test point A9TP7 and adjust
+
10V potentiometer A9R2 for
a
voltme
-
ter indication of
+
10.000
+
0.100 Vdc.
8.
Connect digital voltmeter to VO test point A8TP2. Set spectrum analyzer SWEEP TIME/DIV control to
10 ms and SWEEP TRIGGER control to SINGLE. Turn ALT
IF
and SIG IDENT on (pushbuttons
depressed).
9.
Voltage at A8TP2 will alternate between two values each time a sweep is triggered. Trigger sweep a few
times until voltmeter indicates least negative VO voltage. Adjust VO potentiometer
A8R62 for a voltmeter
indication of
-
2.00
&
0.10 Vdc.