Agilent Technologies 1142A User manual

Agilent Technologies
Agilent 1142A
Probe Control and
Power Module
User’s Guide

Notices
© Agilent Technologies, Inc. 2000 – 2014
No part of this manual may be reproduced in
any form or by any means (including elec-
tronic storage and retrieval or translation
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ment and written consent from Agilent
Technologies, Inc. as governed by United
States and international copyright laws.
Manual Part Number
01142-97003
Edition
August 2014
Printed in Malaysia
Agilent Technologies, Inc.
1601 California Street
Palo Alto, CA 94304, USA
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or consequential damages in connection
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Safety Notices
CAUTION. A CAUTION notice
denotes a hazard. It calls attention to
an operating procedure, practice, or the
like that, if not correctly performed or
adhered to, could result in damage to
the product or loss of important data.
Do not proceed beyond a CAUTION
notice until the indicated conditions
are fully understood and met.
WARNING. A WARNING notice
denotes a hazard. It calls attention to
an operating procedure, practice, or
the like that, if not correctly per-
formed or adhered to, could result in
personal injury or death. Do not pro-
ceed beyond a WARNING notice until
the indicated conditions are fully
understood and met.
2 N2779A User’s Guide

3
1142A Probe Control and Power Module
1142A Probe Control and
Power Module
Using the 1142A 5
Safety Information 8
Performance Test 11
Specifications and Characteristics 13
Service 15
Replaceable Parts 19
Contacting Agilent 32
The 1142A supplies two sets of positive and negative
voltages for use by active probes. For the 1141A probe it
also supplies an offset current. Refer to the 1141A
Differential Probe and 1142A Probe Control and Power
Module User and Service Guide for more information.
Figure 1 1142A Probe Control and Power Module

4
1142A Probe Control and Power Module
Before connecting your Agilent probe to the 1142A, refer to the
probe’s user’s guide to learn how to perform measurements. This
manual contains information for use and service of the 1142A by
itself. It covers use of the 1142A as a power supply only and
service of the instrument in general. Use of the offset controls is
covered in the probe or oscilloscope manual.
Parts Supplied The following items are supplied with the 1142A.
■One power cord
■One operating and service guide
Accessories Available A fan- out adapter is available to power two probes with one
supply.
■Fan- out adapter, part number 01144- 61604
Instruments Covered by
Manual
The 1142A’s rear- panel serial number sticker is in the form:
0000A00000. The first four digits and letter are the serial prefix,
while the last five digits are the suffix. The prefix is the same for
all identical instruments, and it changes only when a change has
been made to the instrument. The suffix however, is assigned
sequentially and is different for each instrument. The contents of
this manual apply to instruments with the serial number prefixes
3050A.

1142A Probe Control and Power Module
Using the 1142A
5
Using the 1142A
This section of the manual contains information and
instructions for installation and use of the 1142A Probe
Control and Power Module as an auxiliary power supply. Use
of probe controls is covered in the guide for the probe.
Initial Inspection
1Inspect the shipping container for damage. Keep a damaged
shipping container or cushioning material until the contents
of the shipment have been checked for completeness and the
instrument has been checked mechanically and electrically.
2Check the accessories. If the contents are incomplete or
damaged notify your Agilent Technologies Sales Office.
3Inspect the instrument.
aIf there is mechanical damage or defect, or if the
instrument does not operate properly or pass performance
tests, notify your Agilent Technologies Sales Office.
bIf the shipping container is damaged, or the cushioning
materials show signs of stress, notify the carrier as well
as your Agilent Technologies Sales Office. Keep the
shipping materials for the carrier's inspection. The Agilent
Technologies Office will arrange for repair or replacement
at Agilent Technologies' option without waiting for claim
settlement.

6
1142A Probe Control and Power Module
Using the 1142A
Checking the Power
Requirements and Fuse
The power module requires a power source of either 115 Vac
or 230 Vac, 47 to 440 Hz, 25VA maximum.
CAUTION BEFORE CONNECTING POIWER TO THIS INSTRUMENT, be
sure the line voltage select switch on the instrument’s rear
panel is set properly. Applying a voltage excessive to the setting
may open the protective fuse.
The rear- panel fuse (F1) is a 0.25A, 250V time- delay fuse.
The fuse used is the same regardless of line voltage
selection. To replace the fuse:
1Locate the fuse holder shown in Figure 2. Gently push the
fuse holder in using your finger or a flat- bladed screwdriver.
2While the fuse holder is pushed in, gently turn the fuse
holder counterclockwise.
Figure 2 1142A Rear Panel

1142A Probe Control and Power Module
Using the 1142A
7
WARNING SHOCK HAZARD!BEFORE YOU CONNECT THIS INSTRUMENT TO MAINS
POWER OR LIVE MEASURING CIRCUITS you must provide a protective
earth ground. The Mains plug must be inserted in a socket outlet
provided with a protective earth contact. Do not use an extension cord
(power cable) without a protective conductor (grounding). Grounding
one conductor of a two-conductor outlet does not provide an instrument
ground. Failure to provide a protective earth ground could result in a
shock hazard if there is a failure in this instrument or equipment
connected to it.
The 1142A is provided with a three- wire power cable. When
connected to an appropriate ac power outlet, this cable grounds the
instrument cabinet. The type of power cable plug shipped with the
instrument depends on the country of destination.
The 1142A has no power switch. It is not required because of the
low mains power requirement.
To Clean the Instrument If the 1142A requires cleaning, perform the following steps:
1Remove power from the instrument.
2Clean the external surfaces of the instrument with a soft,
dry cloth. Make sure that the instrument is completely dry
before reconnecting it to a power source.

8
1142A Probe Control and Power Module
Safety Information
Safety Information
The following general safety precautions must be observed during
all phases of operation of this instrument. Failure to comply with
these precautions or with specific warnings or operating
instructions in the product manuals violates safety standards of
design, manufacture, and intended use of the instrument. Agilent
Technologies assumes no liability for the customer's failure to
comply with these requirements.
Table 1 Instrument Markings
Marking Description
Instruction manual symbol: the product is marked with this symbol when it is necessary for you to
refer to the instruction manual in order to protect against damage to the product. "Caution" or
"Warning" risk of danger marked on product. Refer to “Safety Information” on page 8.
Hazardous voltage symbol.
Earth terminal symbol. Used to indicate a circuit common connected to grounded chassis.
Indicates AC (Alternating Current).
The CE mark of the European Community.
The CSA mark.
This symbol indicates the Environmental Protection Use Period (EPUP) for the product’s toxic
substances for the China RoHS requirements.
This product complies with the WEEE Directive marking requirements.

1142A Probe Control and Power Module
Safety Information
9
General Do not use this product in any manner not specified by the
manufacturer. The protective features of this product may be
impaired if it is used in a manner not specified in the operation
instructions.
WARNING Only fuses with the required rated current, voltage, and specified type
(normal blow, time delay, etc.) should be used. Do not use repaired fuses
or short-circuited fuseholders. To do so could cause a shock or fire
hazard.
This apparatus has been designed and tested in accordance with
IEC Publication 348, Safety Requirements for Measuring Apparatus,
and has been supplied in a safe condition. This is a Safety Class I
instrument (provided with terminal for protective earthing). Before
applying power, verify that the correct safety precautions are taken
as described in the following warnings. In addition, note the
external markings on the instrument as described in Table 1 on
page 8.
WARNING If the instrument is damaged, or if it fails to operate according to the
characteristics in this manual, remove the power cord and contact
Agilent Technologies.
WARNING Before turning on the instrument, you must connect the protective earth
terminal of the instrument to the protective conductor of the (mains)
power cord. The mains plug shall only be inserted in a socket outlet
provided with a protective earth contact. You must not negate the
protective action by using an extension cord (power cable) without a
protective conductor (grounding). Grounding one conductor of a
two-conductor outlet is not sufficient protection.
WARNING If you energize this instrument by an auto transformer (for voltage
reduction or mains isolation), the common terminal must be connected
to the earth terminal of the power source.
WARNING Whenever it is likely that the ground protection is impaired, you must
make the instrument inoperative and secure it against any unintended
operation.

10
1142A Probe Control and Power Module
Safety Information
WARNING Service instructions are for trained service personnel. To avoid
dangerous electric shock, do not perform any service unless qualified to
do so. Do not attempt internal service or adjustment unless another
person, capable of rendering first aid and resuscitation, is present.
WARNING Do not install substitute parts or perform any unauthorized modification
to the instrument.
WARNING Capacitors inside the instrument may retain a charge even if the
instrument is disconnected from its source of supply.
WARNING Do not operate the instrument in the presence of flammable gases or
fumes. Operation of any electrical instrument in such an environment
constitutes a definite safety hazard.
WARNING When unplugging the power cord from the power receptacle or from the
unit, grasp the plug, not the cord, in order to avoid damaging the cable.

1142A Probe Control and Power Module
Performance Test
11
Performance Test
This section documents the Output Voltages Performance Test
which tests the electrical performance of the 1142A. There are no
service adjustments.
The performance test procedures may be performed for incoming
inspection of the instrument and should be performed periodically
thereafter to ensure and maintain peak performance. Amount of
use, environmental conditions, and the user's experience concerning
need for testing will contribute to verification requirements.
NOTE If this supply is used with an 1141A Differential Probe, use the procedures
in the user and service guide supplied with the probe.
Equipment Required A DVM with 0.5% accuracy or a 34401A digital multimeter is
required.
Adjustments There are no service adjustments on the 1142A.
Output Voltages
Performance Test
The output voltages are tested at the rear- panel connector.
1Connect the instrument to the mains power.
2Measure the power supply voltages (±6V and ±15V, ±3.0%) on
the rear- panel power connector as listed in Table 2 on
page 12.

12
1142A Probe Control and Power Module
Performance Test
Table 2 Voltage Outputs on Rear-Panel Connector
Connector Pin Voltage
1LFSignal
2 Offset Out
3+6V
4–15V
5 Offset Common
6+15V
7 Power Common
8–6V

1142A Probe Control and Power Module
Specifications and Characteristics
13
Specifications and Characteristics
There are no specifications for the 1142A Probe Control and Power
module as a stand- alone instrument. As it is designed to be used
specifically with certain active probes, its characteristics are
coupled with the performance of the probe. When used only as a
power supply, the 1142A provides ±6V and ±15V at ±3%.
General Characteristics The following characteristics apply to the 1141A Differential Probe
with the 1142A Probe Control and Power Module.
Table 3 Environmental Conditions
Item Characteristic
Use Indoor
Te m p e r at u r e
Operating 0° C to +55° C (32° F to +131° F)
Non-operating –40° C to +70° C (-40° F to +158° F)
Humidity
Operating Up to 95% relative humidity (non-condensing) at +40° C (+104° F)
Non-operating Up to 90% relative humidity at +65° C (+149° F)
Altitude
Operating Up to 4,600 meters (15,000 ft)
Non-operating Up to 15,300 meters (50,000 ft)
Vibration
Operating Random vibration 5 to 500 Hz, 10 minutes per axis, 0.3, Grms.
Non-operating Random vibration 5 to 500 Hz, 10 minutes per axis, 2.41 Grms. Resonant search 5 to 500 Hz swept
sine, 1 Octave/minute sweep rate, (0.75G), 5 minute resonant dwell at 4 resonances per axis.

14
1142A Probe Control and Power Module
Specifications and Characteristics
Figure 3 Dimensions
Recommended Test
Equipment
The only piece of test equipment needed for testing and
troubleshooting this instrument is a digital multimeter with at least
0.5% voltage measurement accuracy. A 34401A is sufficient.
Table 4 Power Requirements
Item Specification
Voltage 115/230 Vac, 47 to 440 Hz
Power 25 VA maximum
Table 5 Weight
Item Specification
Net 1.8 kg (4.0 lb)
Shipping approximately 2.7 kg (6.0 lb)

1142A Probe Control and Power Module
Service
15
Service
This section provides troubleshooting, service, and repair
information for the 1142A Probe Control and Power Module. The
troubleshooting information is provided to isolate a faulty assembly.
When a faulty assembly has been located, the disassembly/assembly
procedures help direct replacement of the assembly.
The service policy for the 1142A Probe Control and Power Module
is component- level repair.
Safety Read the “Safety Information” on page 8 before servicing the
instrument. Before performing any procedure, review it for cautions
and warnings.
WARNING Maintenance should be performed by trained service personnel aware
of the hazards involved (for example, fire and electric shock). When
maintenance can be performed without power applied, the power cord
must be removed from the instrument.
Figure 4 Location of Protective Earthing Terminal

16
1142A Probe Control and Power Module
Service
Troubleshooting The circuitry consists of simple power supplies, operational
amplifiers, and TTL logic. Use conventional troubleshooting
techniques. A complete parts list, component location, and
schematics are provided later in this chapter.
Theory of Operation The following discussion covers block- level theory for the 1142A
Probe Control and Power Module.
The control and power module provides offset functions, local and
remote control, and power to an 1141A Differential Probe. For
more complete information about how this power module is used
with the differential probe, see the service section of the user and
service guide for the probe.
Offset Functions
There are two offset functions developed in the control module:
variable offset and dc reject. A variable offset voltage with coarse
and fine adjustments can be selected by the front panel controls.
The offset level is buffered by U8 and selected by multiplexer U3 as
the input to offset amp U7. The output of the offset amp is
summed with the low frequency signal and feedback which gives dc
coupling in the probe.

1142A Probe Control and Power Module
Service
17
Figure 5 A1 Control and Power Module Block Diagram
Front panel screwdriver adjustment Offset Null zeros the dc output
from the probe when the dc input and offset are zero.
For dc Reject, an output from the low- frequency amplifier in the
probe (LFSIG) is used to develop a voltage used to null the dc
component of the input signal. LFSIG is an input to U6, an
inverting amplifier and low- pass filter. Multiplexer U3 selects one
of three capacitors to set a roll- off frequency of 0.05, 0.5, or 5 Hz.
The output of U6 is selected, again by U3, as the input to the offset
amp. When the output of the offset amp is summed into the low
frequency path, the result is cancellation of the dc component of
the input signal. Front panel screwdriver adjustment DC Reject
Gain adjusts the gain of the dc reject circuit.

18
1142A Probe Control and Power Module
Service
Local and Remote Control
The front panel switch controls the dc reject and offset functions. It
also selects remote operation, which allows control through the rear
panel remote input connector.
Power Supply
The power supply provides ±6V and ±15V for the probe and analog
control circuitry as well as +5V for the digital control circuitry.
Removing and Replacing
Assemblies
Use the following procedure to disassemble the probe control and
power module.
WARNING Hazardous voltages exist on the power supply. To avoid electrical shock,
adhere closely to the following procedures.
1Remove the power cord.
2Remove four flathead screws and remove the top cover.
WARNING Be sure to reconnect the safety ground when reassembling the
instrument.
3Unplug the safety ground from the tab on the rear panel of
the instrument.
4Note the orientation of the knobs. Remove the two knobs.
5On the bottom of the instrument, remove the 5 mm screw
that fastens the transformer support.
6Remove the following pan- head screws.
■Three directly on the PC board.
■Two on the ac input connector.
■Two on the heat sink.
7Remove the PC board. Slide it slightly forward so parts will
clear the rear panel, then lift the rear of the board out while
sliding it backwards.
8Remove the two heat sink spacers from the standoffs that
were directly under the heat sink.
9Reverse the procedure to reassemble the control and power
supply.

1142A Probe Control and Power Module
Replaceable Parts
19
Replaceable Parts
This section contains information for ordering parts. Service
support for the 1142A is to the component level.
Ordering Information To order a part in the material list, quote the part number, indicate
the quantity desired, and address the order to the nearest Agilent
Technologies Sales Office.
To order a part not listed in the material list, include the
instrument part number, instrument serial number, a description of
the part (including its function), and the number of parts required.
Address the order to the nearest Agilent Technologies Service
Center.
Direct Mail Order System Within the USA, Agilent Technologies can supply parts
through a direct mail order system. There are several
advantages to this system:
■Direct ordering and shipment from the Agilent Technologies
parts center in California, USA.
■No maximum or minimum on any mail order (there is a
minimum amount for parts ordered through a local Agilent
Technologies Sales Office when the orders require billing and
invoicing).
■Prepaid transportation (there is a small handling charge for each
order).
■No invoices.
In order for Agilent Technologies to provide these advantages, a
check or money order must accompany each order.
Mail order forms and specific ordering information are available
through your local Agilent Technologies office. Addresses and
telephone numbers are located in a separate document shipped
with the manuals.

20
1142A Probe Control and Power Module
Replaceable Parts
Manufacturers' Codes A list of manufacturers' codes is given in Table 6 on page 20. The
codes are given for parts in the parts lists. The table gives the
manufacturer and address for each code.
Parts Lists The replaceable parts lists include all parts relevant to the
applicable service levels. Table 7 on page 21 lists the replaceable
parts to the assembly level. Table 8 on page 22 lists parts for the
A1 PC assembly. The information given for each part consists of
the following:
■Reference designator.
■part number.
■Part number Check Digit (CD).
■Total quantity (Qty) in instrument or on assembly. The total
quantity is given once and at the first appearance of the part
number in the list.
■Description of the part.
■Typical manufacturer of part in an identifying five- digit code.
Table 6 Manufacturers' Code List
Mfr. No. Name Address
00000 Any satisfactory supplier
04713 Motorola Semiconductor
Products,
Phoenix,, AZ 85008
06665 Precision Monolithics Inc, Santa Clara,, CA 95050
24546 Corning Glass Works (Bradford) Bradford,, PA 16701
27014 National Semiconductor Corp Palo Alto,, CA 94304
,28480 Agilent Technologies Santa Rosa, CA 95403
32997 Bourns Inc Riverside,, CA 92507