Agilent Technologies 1153A Troubleshooting guide

User and Service Guide
Publication number 01153-97004
July 2004
For Safety and Regulatory information, see the pages after the
index.
© Copyright Agilent Technologies 1991-2004
All Rights Reserved
Agilent Technologies 1153A
Differential Probe

2
Agilent Technologies 1153A Differential Probe
The 1153A Differential Probe allows measurement of small differential
signals in the presence of much larger common-mode signals. The
probe has the following major features:
• 200 MHz bandwidth
• AutoProbe probe interface
• Variable offset
• Lf (low frequency) reject
• Ac coupling
The variable offset capability can be used to measure small ac signals in
the presence of much larger dc levels.
The probe can be used with instruments employing the Agilent
AutoProbe probe interface, such as the Infiniium family of
oscilloscopes
Accessories Supplied
The following accessories are supplied. See “Accessories supplied” in chapter 1 for a
complete list.
• 10:1 attenuator adapter
• 100:1 attenuator adapter
• ac coupling attenuator adapter
• Miscellaneous small accessories
• Carrying Case

Contents
3
1 General Information
To inspect the probe 7
To clean the probe 7
Accessories Supplied 8
Accessories Available 10
Characteristics 11
General Characteristics 12
2 Operating the Probe
Using the accessories 17
Grounding 21
Coupling functions 22
Differential amplifiers and CMRR 24
3Service
Introduction 26
Safety 26
Service Strategy 26
To return the probe to Agilent Technologies for service 27
Probe troubleshooting 28
Preparing the probe for troubleshooting 28
Troubleshooting the probe 28
Removing and replacing the assemblies 30
Differential Probe 30
Probe Adapters 32
Replaceable Parts 34
Ordering replacement parts 34
Replaceable parts 35

5
1
General Information

6
General Information
Introduction
This chapter covers the following information:
• Inspection
• Cleaning
• Accessories supplied
• Accessories available
• Specifications
• Characteristics
• General characteristics

7
General Information
To inspect the probe
To inspect the probe
• Inspect 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.
• Check the accessories
Accessories supplied with the instrument are listed in “Accessories Supplied” later
in this chapter.
• If the contents are incomplete or damaged notify your Agilent Technologies sales
office.
• Inspect the instrument.
• If there is mechanical damage or defect, or if the instrument does not operate
properly or pass calibration tests, notify your Agilent Technologies Sales Office.
• If the shipping container is damaged, or the cushioning materials show signs of
stress, notify the carrier as well as your sales office. Keep the shipping material
for the carrier’s inspection. The Agilent Technologies office will arrange for repair
or replacement at Agilent Technologies option without waiting for claim
settlement.
To clean the probe
If this probe requires cleaning, disconnect it from the oscilloscope and clean it with a
mild detergent and water. Make sure the instrument is completely dry before
reconnecting it to the oscilloscope.

8
General Information
Accessories Supplied
Accessories Supplied
The following items are supplied as part of the 1153A probe. Item
numbers refer to the numbers in the figures on pages 9 and 10.
Accessories supplied with Probe System
Item Description Qty Part Number
1 Differential Probe 1
2 10:1 Attenuator Adapter 1 5063-2144
3 100:1 Attenuator 1 5063-2145
4 ac Coupling Adapter 1 5063-2146
5 Two-inch Extension Leads (package 5) 1 5959-9334
6 Mini Grabber 2 1400-1422
7 Five-inch Ground Lead 1 5061-6162
8 Shielded Signal Lead 1 01141-68702
9 Test Board 1 01141-66504
10 Flat-blade Alignment Tool 1 8710-1961
11 Circuit Connection Posts (strip of 20) 1 1251-5943

9
General Information
Accessories Supplied
Figure 1-1
1153A Differential Probe and Accessories
423
1
5
6
7
8

10
General Information
Accessories Available
Figure 1-2
1153A Miscellaneous Accessories
Accessories Available
The following accessories are available for use with the 1153A:
• 5959-9335 Long Extension Lead (5.5 inch/14 cm), package of 5
• 5090-4833 SMT clip, package of 20
• 10467-68701 Micro Clip, package of 4

11
General Information
Characteristics
Characteristics
The following table gives characteristics for the probe.
Table 1-1
Characteristics
Parameter Probe alone With 10:1 attenuator With 100:1 attenuator
System bandwidth 200 MHz with 54800 family of oscilloscopes
dc gain accuracy 2.0% with 50 ±0.1 Ωload 4.0% with 50 ±0.1 Ωload
Maximum Input Voltage
(see figure1-3)
±200 V(dc + peak ac), CAT I
CMRR See the figure 1-4
Rise Time 1.75 ns calculated from tr = (0.35/bandwidth)
Linear differential input range
DC mode with no offset ±300 mV peak ±3.0 V peak ±30 V peak
with IF reject or appropriate offset ±18 Vdc, decreasing to
±300 mv at 30 Hz
±180 Vdc, decreasing to
±3.0 V at 30 Hz
±500 Vdc, decreasing to
±30 V at 30 Hz
Common-mode operating
range dc ±18 Vdc ±180 Vdc ±500 Vdc
dc to 30 Hz linear decreased to 30 Hz value
30 Hz to 200 MHz ±0.5 V peak ±5 V peak ±50 V peak
dc offset range ±18 V ±180 V ±500 V
Input Impedance Resistance
Capacitance
1 MΩ
7 pF
9 MΩ
3.5 pF
10 MΩ
2 pF
ac coupling low-frequency1
response (-3dB)
15 Hz 1.5 Hz 1.5 Hz
LF reject response 1.7 Hz (LFR1) and 0.14 Hz (LFR2)
Output termination impedance 50 Ω
Displayed noise ≤500 µVrms
Overload recovery < 1 ms from overdrive that is less than the common mode range
1For maximum signal fidelity above 100 MHz, limit the probe input (without attenuators) to ≤300 mV peak-to-peak

12
General Information
General Characteristics
General Characteristics
The following table gives general characteristics for the probe.
Environmental Conditions
Operating Non-operating
Temperature 0°C to +55 C° (32°F to +131°F) -40°C to +70°C (-40°F to +158°F)
Humidity up to 95% relative humidity (non-
condensing) at +40°C (+104°F)
up to 90% relative humidity at +65°C
(+149°F)
Altitude up to 4,600 meters (15,000 ft) up to 15,300 meters (50,000 ft)
Vibration Random vibration 5 to 500 Hz, 10
minutes per axis, 0.3grms.
Random vibration 5 to 500 Hz, 10 min.
per axis, 2.41 grms. Resonant search 5
to 500 Hz swept sine, 1 octave/min.
sweep rate, (0.75g), 5 min. resonant
dwell at 4 resonances per axis.
Power
Requirements
+12 Vdc @ 33 mA max
-12 Vdc @ 16 mA max (voltages supplied
+6 Vdc @ 80 mA max from AutoProbe Interface)
-6 Vdc @ 130 mA max
Weight approximately 0.59 (1.3 lb)
Dimensions Refer to outline drawings on the next page.

13
General Information
General Characteristics
Figure 1-3
1153A Differential Probe Dimensions

15
2
Operating the Probe

16
Operating the Probe
Introduction
This section of the manual contains information and instructions for:
• Using accessories
• Grounding the probe
• Probe coupling
• Discussion of common mode rejection ratio (CMRR) and differential amplifiers

17
Operating the Probe
Using the accessories
Using the accessories
The 1153A Differential Probe and accessories provide a variety of ways to connect to
circuitry and make measurements. In the descriptions, any method used to connect to
the probe signal inputs also applies to the adapters. The figure below shows, in a general
way, the use of accessories.
Figure 2-1
Basic Accessory Connections

18
Operating the Probe
Using the accessories
Probe tips Probe tips fit into the receptacles in the probe and are held in place with probe tip caps.
If necessary, you can solder the probe tips into a circuit or wires can be soldered to the
tips. If you solder to the probe tips, be careful not to melt the plastic tip caps.
NOTE Because of the close tolerances between the probe tip caps and probe tips, it will be
difficult to separate the probe tips and caps once the probe tips have been soldered.
Ground lead The circular end of the ground lead fits over the screw on the top side of the probe (see
the previous figure).
Extension leads The extension leads provide a flexible connection between circuitry and the probe.
• To provide a male connection to other circuitry, connect the extension lead over the
probe tips.
• To provide a female connection, remove the probe tip caps and probe tips and connect
the extension leads to the probe.
CAUTION Use extension leads and similar connection accessories carefully. Extension leads
compromise the high-frequency specifications of the probe. CMRR is particularly
sensitive to unbalanced input parameters.
To prevent pickup of stray fields when you use extension leads, either the ones supplied
with the 1153A or others, dress them carefully as follows:
• Connect the leads at right angles to the circuitry under test.
• Keep the leads as parallel as possible before they connect to the probe.
Mini Clips Mini clips and micro clips can be attached to the probe or adapter through the extension
leads.
1Remove the probe tip caps and tips.
2Attach the extension leads to the probe adapter.
3Attach the mini or micro grabbers to the extension leads.
Circuit connector
posts
These 0.025-inch square posts can be used to connect either directly to the probe or to
the extension leads.
Solder the posts directly into your circuitry or use them to make extension leads that
plug into the inputs of the probe or adapters.
Shielded signal
leads
The shielded signal leads allow connection to points in a circuit that are up to 10 inches
apart. The leads are shielded to within approximately 1/2 inch of the end of the lead so
they minimize pick-up due to stray fields from adjacent circuitry.
1Connect the end with the ground connector to the probe pins and ground of
the differential probe or adapter.
2Connect the free ends of the leads to 0.025-inch square or 0.030-inch round pins
in your circuitry or to the mini-grabbers.

19
Operating the Probe
Using the accessories
NOTE Each lead has an input capacitance of approximately 15 pF. This capacitance may limit
the bandwidth of your measurement (depending on the impedance of the circuit). Also,
CMRR may be affected because of slight differences between the input capacitance of
the two leads. CMRR is also affected by differences in impedance between the two
measurement points.
Adapters There are three adapters for use with the differential probe. Two adapters are
attenuators, a 10:1 and a 100:1. The other is an ac adapter for blocking dc from the probe
input.
The adapters are installed on the probe after the probe tip caps and probe tips have been
removed. The adapter fastens to the probe using a thumbwheel located on the underside
of the adapter. The figure below shows a good way to hold the probe while attaching the
adapter.
1Remove the probe tip caps and probe tips from the probe.
2Fit the adapter over the end of the probe and rotate the thumbwheel with your
finger until the adapter fits snugly.
A snug fit is important because the ground is maintained through the thumbwheel screw.
A loosely attached adapter compromises the mechanical and electrical integrity of the
combination.
Figure 2-2
Attaching the adapters

20
Operating the Probe
Using the accessories
Adapter
combination
The figure below shows the allowed adapter and probe combinations. There are two
specific combinations that should not be used.
• Do not attach the ac adapter between an attenuator adapter and the probe.
An attenuator adapter must be terminated by the input resistance of the probe. The
ac adapter isolates the probe input resistance.
• Do not cascade two attenuator adapters.
The attenuator adapters are designed to be terminated by the 1 MΩresistance of the
probe. The input resistance of the attenuator adapters is 9 MΩ for the 10:1 adapter
and 10 MΩ for the 100:1 adapter.
Figure 2-3
Allowed adapter combinations

21
Operating the Probe
Grounding
Connector
compatibility
The following are general connector characteristics for the probe, adapters, and
accessories.
• The female connectors on the probe, adapters, and other accessories are designed to
mate with 0.030-inch round or 0.025-inch square pins.
• The probe, adapter, and extension lead pins are 0.030-inch round.
• The strip of circuit connection posts provided as an accessory has 0.025-inch square
pins.
• The mini-grabber has a 0.025-inch square pin.
• The ground connection at the end of the probe and adapters (where the adapters
fasten) accepts an M3 metric screw.
Test board The primary use of the test board is to apply test and calibration signals to the inputs of
the probe or adapters. Specific use of the test board is covered wherever it applies.
Grounding
Grounding is very important when probing circuitry. Improper grounding can increase
the common mode signal level. This reduces the effectiveness of the differential probe.
The mechanical connections at the input of the probe are ground for probe signals. The
screw where the ground lead attaches (see figure below) fastens to this ground. Also,
the attenuator and ac adapters fasten to this ground through the screw connection and
the ground is carried through each adapter to its front.
Figure 2-4
Probe grounds

22
Operating the Probe
Coupling functions
Coupling functions
There are three methods for blocking or compensating for the dc component of a signal.
Each has specific advantages.
Probe system coupling functions
Lf Reject Lf reject is the best method of eliminating the dc component of a signal when dc is not
a factor in the measurement. Remove the ac adapter if it is installed. The key
characteristics are:
• The low frequency component (from dc to the selected corner frequency) is
automatically nulled by the IF reject circuitry.
• Probe CMRR specifications are not compromised as happens when the ac coupling
adapter is used.
• There is a selectable low frequency corner with -3dB points at 1.7 Hz (LFR1) or 0.14Hz
(LFR2).
• The voltage reject range is ±18 V with the probe alone, ±180 V with the 10:1
attenuator, and ±500 V with the 100:1 attenuator.
With the frequency and voltage characteristics noted elsewhere in this manual, low
frequencies are nulled from the input signal.
dc Offset If Reject ac Coupling Adapter
dc Blocked
Probe alone
Probe with 10:1
Probe with 100:
±18 V
±180 V
±500 V
±18 V
±180 V
±500 V
±200 V
±500 V
±500 V
Set-up needed Adjust offset to put
signal on screen
Select If Reject
low-frequency
corner
Attach ac Coupling
adapter to differential
probe
Remote Control? Yes1Yes1No
CMRR
degradation?
No No No
Low-frequency
degradation?
No Yes Yes
1Isolated external dc reference and control signals are needed.