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User and Service Guide
Publication number 01141-97002
July 2004
For Safety and Regulatory information, see the pages at the end
of this book.
© Copyright Agilent Technologies 2000-2004
All Rights Reserved
Agilent Technologies 1141A
Differential Probe and 1142A
Probe Control and Power
Module
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Agilent Technologies 1141A Differential Probe and 1142A Probe Control and Power Module This manual contains information for use and service of the differential probe system, the 1141A Differential Probe and 1142A Probe Control and Power Module. In this document, the two models will be treated as a system. Each of the two instrument models that make up the differential probe system has a serial number sticker. The sticker for the 1141A Differential Probe is inside the probe, in the bottom c
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Contents 1 Operating the Probe Accessories Supplied 6 Accessories Available 8 To inspect the probe 9 Using the probe with other instruments 9 Recommended Test Equipment 9 2 Calibration Tests and Adjustment Equipment Required 26 The Test Board 26 Calibration Tests 27 dc Gain Accuracy 28 Bandwidth 34 CMRR Test 36 Calibration Test Record 39 Adjustments 40 Probe Adjustment 40 Adjustment Procedure 42 Attenuator Adapter Adjustment 49 3Service Introduction 54 Performance Specifications and Characterist
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Contents Theory of Operation 59 Differential Probe 60 Control and Power Module 60 Attenuator Adapters 61 Test Board 62 Service Policy 63 Troubleshooting 64 Probe Troubleshooting 64 Probe Control and Power Module Troubleshooting 64 Removing and Replacing Assemblies 66 Differential Probe 66 Probe Adapters 68 Probe Control and Power Module 70 Replaceable Parts 71 Parts List 71 Ordering Information 71 Direct Mail Order System 71 Manufacturers’ Codes 72 Exploded View 73 4
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1 Operating the Probe 5
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Operating the Probe Accessories Supplied Introduction This chapter shows you how to connect and operate the 1141A Differential Probe and 1142A Probe Control and Power Module as a differential probe system. Accessories Supplied The following items are supplied as part of the 1141A/1142A probe system. Item numbers refer to the numbers in Figure 1-1 on page -7 and Figure 1-2 on page -8. Those without item numbers are supplied but not shown in figures. See the Replaceable Parts List for parts
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Operating the Probe Accessories Supplied Figure 1-1 1141A Differential Probe and Accessories 7
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Operating the Probe Accessories Available Figure 1-2 1141A Miscellaneous Accessories Figure 1-3 1142A Probe Control and Power Module Accessories Available The following accessories can be ordered. • 5959-9335 Long Extension Lead (5.5 inch/14 cm), package of 5 • 5090-4833 Mini grabber for SMT, package of 20 8
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Operating the Probe To inspect the probe To inspect the probe Inspect the shipping container for damage. If the shipping container or cushioning material is damaged, it should be kept until the contents of the shipment have been checked for completeness and the instrument had been checked mechanically and electrically. Accessories supplied with the instrument are listed in see “Accessories Supplied” on page 6 of this manual. If the contents are incomplete, if there is mechanical damage or d
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Operating the Probe Recommended Test Equipment Recommended Agilent Equipment Required Critical Specifications Model/Part Use Test Board No substitute (supplied accessory) 01141-66504 A Load BNC Feedthrough, 50 Ω Pasternack P Enterprises PE6008- 50 or Huber+Suhner 22543742 Cables (2) BNC, 50 Ω 36-inch 10503A P,A Cable BNC, 50 Ω 9-inch 10502A A Cable Type N (m) 24-inch 11500B P Adapter Type N (m) to BNC (f) 1250-0780 A Adapter Type N (f) to BNC (m) 1250-0077 P Adapters (2) BNC (f) to dual banana
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Operating the Probe Recommended Test Equipment WARNING Before connecting this instrument, the protective earth terminal of the instrument must be connected to the protective conductor of the (Mains) power cord. The Mains plug must be inserted in a socket outlet provided with a protective each contact. The protective action must be negated by the use on an extension cord (power cable) without a protective conductor (grounding). Grounding one conductor of a two- conductor outlet does not provi
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Operating the Probe Recommended Test Equipment • Offset null zeroes the dc level at the output of the probe. The range of adjustment is about ±4 mV. • DC Reject Gain adjusts the gain of the dc reject circuit to accurately null the dc component of an input signal. The range of adjustment is about ±0.5%. Figure 1-5 1142A Front Panel Equipment Needed The following equipment is necessary for initial adjustment. • 5 V power supply • DVM that can measure 25 µV •50 Ω BNC feedthrough terminator • 0114
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Operating the Probe Recommended Test Equipment 5 Set up the 1142A: a Set the Local/Remote push button to Local. b Under DC Couple, press Zero offset. 6 Set the power supply output to 5 V. 7 Arrange a connection between the power supply and the test board. The negative terminal of the supply should connect to the shield of the test board BNC. If your power supply has standard binding posts, you can connect a banana-to-BNC adapter to the supply and connect a BNC cable between the supply and the
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Operating the Probe Recommended Test Equipment Figure 1-7 Basic Accessory Connections 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 probe 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
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Operating the Probe Recommended Test Equipment Note 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 lead, either the ones supplied with the 1141A or others, dress them carefully as follows: • Connect the leads at right angles to the circuitry under test. • Keep the leads as parallel
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Operating the Probe Recommended Test Equipment Adapters There are three adapters for use with the differential probe. Two adapters are attenuators, a 10x and a100x. 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 thumb wheel located on the underside of the adapter. the figure below shows a good way to hold the probe while attaching the
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Operating the Probe Recommended Test Equipment Adapter Combinations The figure below shows the allowed adapter and probe connections. 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
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Operating the Probe Recommended Test Equipment 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 0.0250-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 0.25-
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Operating the Probe Recommended Test Equipment Probe System Coupling Functions dc offset dc Reject ac Coupling Adapter dc Blocked Probe alone ± 20 V ± 20 V ± 20 V ± 200 V ± 200 V ± 500 V Probe with 10x ± 500 V ± 500 V ± 500 V Probe with 100x Adjust offset to put Select DC Reject Attach ac Coupling Set-up needed signal on screen low-frequency adapter to corner differential probe 1 1 Remote Control? Yes Yes No CMRR No No Yes degradation? Low-frequency No Yes Yes degradation? 1 Isolated externa
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Operating the Probe Recommended Test Equipment To use dc reject: 1 Remove the ac adapter if it is installed. 2 On the front panel of the 1142A, press Local. 3 Under DC Reject on the front panel, press 5.0 Hz or 0.5 Hz individually, or 5.0 Hz and 0.5 Hz simultaneously to get 0.05 Hz. Within the frequency and voltage characteristics noted elsewhere in this manual, low frequencies are nulled from the input signal. Offset Offset is the best method to use when the low-frequency corners associated w
