Agilent Technologies 33120A User manual

This guide contains information to install the Phase-Lock assembly into
the Agilent 33120A. This assembly can be installed only in instruments
shipped after August 1994 with serial numbers US34004078 and above.
Refer to the Agilent 33120A/Option 001 User’s and Service Guide
(included with the retrofit kit) for complete details on using the assembly.
Installing the Phase-Lock Assembly
1 Remove the outer cover from the Agilent 33120A.
Page 1
Agilent 33120A
Option 001 Phase-Lock Assembly
Installation Instructions for 33120-80001 Retrofit Kit
Loosen
Captive
Screws
Remove
Bottom Screw
Slide Off Outer Cover
a
b

2 Carefully cut two holes in the rear-panel label.
The Ref Out and Ext Ref In terminals on the Phase-Lock assembly will
extend through these holes in the 33120A rear-panel. Pierce the label in
the center of the chassis holes and then cut to the outer edge of the holes.
Then, let the chassis holes guide the knife around the edge of the hole.
3 Connect the coaxial cable to the Phase-Lock circuit board.
Connect one end of the coaxial cable (included with the retrofit kit) to
the connector labeled P2 on the Phase-Lock circuit board. Position the
cable as shown.
2
Cut Out Label
to Chassis Holes
Coaxial Cable (33120-61603)
P2
P2

4 Install the Phase-Lock assembly in the Agilent 33120A chassis.
Before installing the Phase-Lock assembly, make sure that the red and
black wires for the instrument fan are clear of the rear-panel holes.
With the Phase-Lock assembly positioned component side down,
insert the two BNC connectors through the holes previously cut in
the rear-panel label.
5 Secure the Phase-Lock assembly in place.
As shown above, place one lock washer and one hex nut (included with
the retrofit kit) on each of the two BNC connectors. To prevent cross-
threading, be sure to hand-tighten the hex nuts at least one turn before
using a tool.
3
Lock Washer (2190-0699)
Hex Nut (2940-0256)
Component Side
Down
Top View
Side View

6 Connect the coaxial cable to Agilent 33120A circuit board.
First, slide the black ferrite bead to the end of the coaxial cable as shown.
Then, connect the coaxial cable to connector J401 on the 33120A circuit
board. Be sure to position the cable away from the heatsinks on the
circuit board.
7 Connect the ribbon cable to the Agilent 33120A circuit board.
Connect the loose end of the grey ribbon cable to connector J102 on the
33120A circuit board. Press down firmly on the ribbon cable connector
and secure the cable in place with the locking clips.
4
Ferrite Bead
J401
Ribbon
Cable
J102
Snap the Locking Clips
over the top of the connector
to secure the Ribbon Cable.

Calibration /Adjustment Procedure
After installing the Phase-Lock assembly, perform the frequency
adjustment procedure (CAL:SETup 86) on page 69 in the Agilent
33120A Service Guide. Be sure to make the 10 MHz frequency
measurement with an accuracy of at least 8 digits (0.01 ppm). It may
be necessary to perform up to three iterations of the frequency
adjustment following the initial installation of the Phase-Lock assembly.
Installation of the Phase-Lock assembly requires that you perform
only the frequency adjustment (CAL:SETup 86) as outlined above,
no further calibration steps are required.
For complete details on performing a calibration, see chapter 4 in
the Agilent 33120A Service Guide.
If you intend to perform an entire calibration at the time you install the
Phase-Lock assembly or in the future, CAL:SETup 86 should replace
CAL:SETup 00 as the first step. You will have to manually change from
setup 00 to setup 86 for this. With “SETUP ^00” displayed on the front
panel, press the “Enter Number” key, the “8” key, the “6” key, and then
press the “Enter” key.
Note that while the instrument automatically steps through setup
numbers as you perform calibration steps, it does not automatically step
from setup 86 to setup 01 (the next calibration step). Therefore, after
performing the frequency calibration adjustment, the instrument will
display “SETUP ^86”. At this point, press the “Enter Number” key,
the “0” key, the “1” key, and then press the “Enter” key. This will return
you to the normal setup sequence starting with “SETUP ^01”.
5

Outside of Rear Cover
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Retrofit Instructions