Adjustments
Model 3585A
5-24
h . Using a DVM , check the Bias voltage at A23TP l . This test point should read -4. 6Vdc
± 0.2V.
i . Move the DVM to A23TP2. Squeeze or expand the oscillator coil (A23L 1 ) to obtain a
voltage of -2.0Vdc ± O. l V .
j . Press " CENTER FREQUENCY.
voltage at A23TP2 is � + 5.0Vdc.
[§JJ
"
on the 3585A and verify that the
k . Turn the 3585A power off. Remove the Step VTO (A23) board from its PC extender
and return it to the card nest . Turn the 3585A power on.
1.
Set the 3585A controls for :
RECALL 60 1
INSTRUMENT PRESET
CENTER FREQUENCy . . . . . . . . . . . . . . . . . . . . . . 0Hz
FREQUENCY SP AN . . . . . . . . . . . . . . . . . . . . . . . . . 0Hz
RES . BW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3KHz
CF STEP SIZE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40MHz
RES . BW HOLD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ON
m. Connect a frequency counter to A23J2. The frequency reading should be 98MHz
± 1 0Hz.
n . Enter:
Center Frequency
[§JJ
o. The Frequency Counter reading should be 1 38MHz ± 1 0Hz.
p . Disconnect the cable at A23 J l . If the frequency counter now reads 1 44MHz
± 0. 5MHz, continue at step u.
q. If the frequency counter reading is not within the limits of 144MHz ± 0. 5MHz, turn
the 3585A power off. Place the Step Phase Detector board (A26) on a PC extender . Turn the
3585A power back on.
r. Set the 3585A controls for :
RECALL 601
INSTRUMENT PRESET
CENTER FREQUENCy . . . . . . . . . . . . . . . . . . . . . . OHz
FREQUENCY SP AN . . . . . . . . . . . . . . . . . . . . . . . . . 0Hz
s. With the cable at A23J1 still disconnected, adjust A26R75 so that the frequency
counter reads 144MHz
±
0. 5 MHz (see Figure 5-20) .
t . Turn the 3585A power off. Replace the A26 board in the card nest and restore power to
the 3585A.
u. Verify that the "STEP " light on the A34 board goes on when the A23 J 1 cable is
disconnected.