Agilent 1142A - Manuals

6 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 syste...

8 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, pack...

9 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 mechanic...

10 Operating the Probe Recommended Test Equipment Setting up the probe The following paragraphs cover system preparation and initial adjustments. Power Requirements The 1141A/1142A probe system (specifically the 1142A) requires a power source of either 90 to 132/198 to 264 Vac, 47 to 440 Hz, 25 VA m...

11 Operating the Probe Recommended Test Equipment W A R N I N G 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 ea...

12 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 ...

13 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 shoul...

14 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 sold...

15 Operating the Probe Recommended Test Equipment N o t e 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...

16 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 an...

17 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...

18 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 squa...

19 Operating the Probe Recommended Test Equipment Probe System Coupling Functions dc Reject dc Reject is the best method of eliminating the dc component of a signal when dc is not a factor in the measurement. The key characteristics are: • The low-frequency component (from dc to the selected corner ...

20 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 fr...

21 Operating the Probe Recommended Test Equipment To use ac coupling: 1 Attach the ac coupling adapter to the input of the probe or the input of the attenuator adapter. 2 On the 1142A, press Local and Zero offset. Remote operation For automatic test applications, the coupling and offset functions pr...

22 Operating the Probe Recommended Test Equipment Function Select The easiest way to control the function select lines is contact closures between the lines and Digital common (pin 2) of the remote input connector. (TTL compatible control signals can be used; but to avoid problems with ground loops,...

23 Operating the Probe Recommended Test Equipment Differential Amplifiers and CMRR The 1141A Differential Probe is a high-impedance differential amplifier. A characteristic of differential amplifiers is the ability to reject signals that are common to the two inputs. The common mode rejection ratio ...

26 Calibration Tests and Adjustment Equipment Required Introduction This chapter is divided into two sections. The first section gives calibration tests and the second adjustment procedures for the 1141A Differential Probe and 1142A Probe Control and Power Module. Equipment Required A complete list ...

27 Calibration Tests and Adjustment The Test Board Calibration Tests These procedures test the probe’s electrical performance using applicable specifications given in “Performance Specifications and Characteristics” on page 55 as performance standards. Specifications applicable to individual tests a...

28 Calibration Tests and Adjustment dc Gain Accuracy dc Gain Accuracy This test checks the dc gain accuracy of the differential probe and the dc accuracy of the differential probe with attenuator and adapters. Specification: Probe alone, ±2%; with attenuator adapter, ±4% Equipment Required Probe Gai...

30 Calibration Tests and Adjustment dc Gain Accuracy Figure 2-3 Signal to - input 10 Calculate probe gain as Record the result of this calculation in the “Calibration Test Record” on page 39. To pass this test, the probe gain = 0.98 to 1.02 N O T E Failure of the gain accuracy test can be caused by ...

32 Calibration Tests and Adjustment dc Gain Accuracy 100x Attenuator Accuracy Test N O T E If the gain test for the probe fails, it will be reflected in the test for the 100x attenuator adapter. Do not continue until the probe passes the gain test. 1 Disconnect the probe/attenuator from the test boa...

33 Calibration Tests and Adjustment dc Gain Accuracy 6 Carefully connect the input of the probe/attenuator to the test board in the position shown in the figure below (signal to - input). Figure 2-7 Signal to - input 7 Record the V out2 measurement from the bottom DVM in figure 2-2. 8 Calculate the ...

34 Calibration Tests and Adjustment Bandwidth Bandwidth This test checks the high-frequency response of the 1141A Differential Probe. The bandwidth of the oscilloscope is characterized first so it is not a factor in the measurement. Specification (-3dB, dc coupled): dc to 200 MHz Equipment Required ...

35 Calibration Tests and Adjustment Bandwidth 6 Reconfigure the equipment. a Disconnect the signal generator cable from the oscilloscope input and connect it to the test board. b Connect the output of the differential probe to the channel 1 input of the oscilloscope. c Carefully connect the input of...

36 Calibration Tests and Adjustment CMRR Test CMRR Test This test checks the CMRR at 1 MHz and 100 MHz. Specification 3000:1 at 1 MHz, 10:1 at 100 MHz Equipment Required Procedure 1 Connect the probe power connector to the PROBE connection on the rear of the 1142A Probe Control and Power Module. 2 S...

37 Calibration Tests and Adjustment CMRR Test 7 On the oscilloscope, press AUTOSCALE and set the following parameters. 8 On the oscilloscope, measure the peak-to-peak voltage of the channel 1 signal, then V P-P, then press 1) and record the reading.V p-p (1) = _____________ mV 9 Connect the input of...

38 Calibration Tests and Adjustment CMRR Test 15 Connect the input of the probe to the test board in the position shown in the figure below (signal to + input). Figure 2-11 Signal to + input 16 Set the signal generator for 100 MHz at 0.0 dBm (about 224 mV rms , 632 mV p-p ). 17 Set the oscilloscope ...

39 Calibration Tests and Adjustment Calibration Test Record Calibration Test Record 1141A/1142A Differential Probe Tested by_________________________ Serial No. ______________________________ Work Order No.____________________ Recommended Test Interval - 1 Year/2000 hours Date____________________ Re...

40 Calibration Tests and Adjustment Probe Adjustment Adjustments This section provides adjustment procedures for the 1141A Differential Probe and attenuator adapters. There are no service adjustments for the 1142A Probe Control Module. Adjustment Interval None of the adjustment procedures that follo...

41 Calibration Tests and Adjustment Probe Adjustment The following equipment is required for this procedure. Procedures are based on the model or part number recommended. Equipment Required Probe Preparation The probe cover must be removed before adjustment. Drift due to temperature differences with...

42 Calibration Tests and Adjustment Adjustment Procedure 6 As shown in the figure below, use the grounding screw to reinstall the ground block on the PC assembly. Figure 2-13 Attaching Ground Block to Probe PC Assembly The ground block provides a mechanical and electrical connection when the probe P...

43 Calibration Tests and Adjustment Adjustment Procedure 3 On the oscilloscope, then press CLEAR DISPLAY. Press AUTOSCALE, then set up the following parameters. 4 On the oscilloscope, measure the peak-to-peak voltage of the channel 1 signal and record the reading.V p-p (1) = _____________ mV 5 Disco...

44 Calibration Tests and Adjustment Adjustment Procedure 8 Center adjustment R11, HF CMRR (see following figure). Figure 2-15 R11, HF CMRR Adjustment 9 Adjust R9, HF GAIN so the V p-p (1) measurement is the same as in step 4, within ±0.5%. Make the adjustment slowly so the oscilloscope display has t...

45 Calibration Tests and Adjustment Adjustment Procedure 2 Change the oscilloscope settings to: 3 Carefully connect the input of the probe to the test board in the position shown in the figure below (signal to + input). Figure 2-17 Signal to + input 4 Adjust R14 (LF Gain) and C4 (+ LF BANDWIDTH) for...

46 Calibration Tests and Adjustment Adjustment Procedure 5 Carefully connect the probe to the test board in position shown in the figure below (signal to both inputs). Figure 2-19 Signal to both inputs 6 Change the function generator settings to: • Sine wave • 4 kHz • 1.0 V p-p 7 Change the oscillos...

47 Calibration Tests and Adjustment Adjustment Procedure High Frequency Compensation This adjustment sequence continues from the Low Frequency Response and CMRR adjustment. However, it can be done separately if the probe meets all specifications except bandwidth. Adjust R13 for unity gain at 200 MHz...

48 Calibration Tests and Adjustment Adjustment Procedure 4 Assemble the PC assembly in the top cover. The side of the PC assembly with the large hybrid is exposed when the assembly is in the top cover. The figure below shows how the top cover, PC board, and ground block fit together. Figure 2-22 Rea...

49 Calibration Tests and Adjustment Attenuator Adapter Adjustment Attenuator Adapter Adjustment The following procedure should be used if it is necessary to adjust an attenuator adapter. Attenuator adapters have only characteristics; they do not have any specifications. An adapter will need adjustme...

50 Calibration Tests and Adjustment Attenuator Adapter Adjustment Adjustment Procedure N O T E The attenuator must be adjusted when installed on the 1141A probe with which it will be used. The specifications and characteristics will not be met if the attenuator adapter is adjusted with one different...

51 Calibration Tests and Adjustment Attenuator Adapter Adjustment 7 Connect the adapter/probe combination to the test board in the position shown in the figure below. Figure 2-23 Signal to + input 8 Adjust the + HF RESP for best overall pulse response, the flattest pulse top. Use the figure below fo...

55 Service Performance Specifications and Characteristics Performance Specifications and Characteristics The following table gives performance specifications used to test the 1141A and 1142A. It also gives performance characteristics that are typical for the probe system. Performance Specifications ...

56 Service Performance Specifications and Characteristics Figure 3-1 CMRR Specifications and Characteristics Legend A. CMRR specification for probe with no input adapters. B. Low-frequency CMRR specification for probe with the ac adapter. C. Typical CMRR characteristic for differential probe with no...

57 Service Performance Specifications and Characteristics Figure 3-2 Maximum Input Voltage vs. Frequency Legend A. Input voltage limits for probe alone. B. Input voltage limits for 10x adapter. C. Input voltage limits for 100x adapter.

58 Service General Characteristics General Characteristics The following characteristics apply to the 1141A Differential Probe with the 1142A Probe Control and Power Module. Figure 3-3 Mechanical Dimensions Environmental Conditions Operating Non-operating Temperature 0°C to +55 C° (32°F to +131°F) -...

60 Service Theory of Operation Differential Probe The probe contains a two-path differential amplifier with unity gain. It is implemented on a double-sided surface-mount PC board with the high-frequency path on one side and the low-frequency path on the other. The two paths are split directly after ...

61 Service Theory of Operation 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 mu...

62 Service Theory of Operation Test Board The test board is a device for conveniently connecting test signals to the differential probe. The probe can be connected to the board with the signal to the positive, negative, or both inputs. Figure 3-6 Test Board Schematic

63 Service Service Policy Service Policy For parts of the 1141A/1142A probe system that are complex, the service policy is for assembly-level repair. For parts of the system with simple circuitry, the service policy is component-level repair. The service policy for the 1141A Differential Probe is as...

64 Service Troubleshooting Troubleshooting Use the following paragraphs to assist in troubleshooting problems with the 1141A/1142A Differential Probe. Probe Troubleshooting To troubleshoot the probe: 1 Apply a known signal to the input of the probe. 2 Check for an identical output at the output coax...

66 Service Removing and Replacing Assemblies Removing and Replacing Assemblies This section contains procedures for the removal and replacement of major assemblies. C A U T I O N Never remove or install any assembly with the instrument power ON. Component damage can occur. Differential Probe Use the...

67 Service Removing and Replacing Assemblies Reassemble Probe The ground screw passes through the top cover and PC board and screws into the ground block. 1 If replacing the PC board, remove the input connectors from the old board and put them on the new one. 2 If replacing the cable, note the orien...

68 Service Removing and Replacing Assemblies C A U T I O N Note where the two pins at the rear of the top cover enter the holes in the PC assembly. Position the cable wires away from these two areas. When the bottom cover is closed, part of it will pinch wires that are laying over these areas. b Ins...

70 Service Removing and Replacing Assemblies Probe Control and Power Module Use the following procedure to disassemble the probe control and power module. W A R N I N G Hazardous voltages exist on the power supply. To avoid electrical shock, adhere closely to the following procedures. 1 Remove the p...

71 Service Replaceable Parts Replaceable Parts This section contains information for ordering parts. Service support for the 1141A Differential Probe is to the assembly level. Service support for the adapters is as complete assemblies, except for the probe tip caps and the probe tips. Service suppor...

72 Service Replaceable Parts Mail order forms and specific ordering information are available through your local Agilent Technologies Sales Office. Addresses and telephone numbers are located in a separate document shipped with the manuals. Manufacturers’ Codes A list of manufacturers’ codes is give...

73 Service Replaceable Parts Exploded View Figure 3-11 1141A Differential Probe Parts

76 Service Replaceable Parts Figure 3-14 1142A Probe Control and Power Module IC Connectors not Shown Supply Pin No. IC Group +15 14 U3 -15 3 GND 15 +15 7 U6-8, 11 -15 4 NC 1, 5, 8 +5 16 U9 GND 8

79 Service Replaceable Parts A1 01142-66501 1 PC ASSEMBLY-POWER AND CONTROL 28480 01142-66501 H1 0515-0374 7 SCREW-MACHINE M3 10mm-LG 00000 ORDER BY DESP. H2 0515-1031 4 SCREW-MACHINE M3 6mm-LG 90-DEG-FLH-HD 00000 ORDER BY DESP. H3 0515-1579 1 SCREW-MACHINE M5 18mm-LG 00000 ORDER BY DESP. MP1 01142-...

80 Service Replaceable Parts Power Supply Replaceable Parts Ref. Des. Part Number Qty Description Mfr. Code Mfr. Part Number Prefix the reference designators with A1 C1 0160-6190 2 CAPACITOR-FXD 0.33UF ±10% 50VDC 28480 0160-6190 C2 0160-5474 1 CAPACITOR-FXD 0.1UF ±5% 100VDC MET-POLY 28480 0160-5474 ...

83 Service Replaceable Parts R16 0698-6317 2 RESISTOR 500 0.1% 0.125W TF TC=0±25 28480 0698-6317 R17 0698-4002 RESISTOR 5K 1% 0.125W TF TC=0±100 24546 CT4-1/8-TO-5001-F R18 0699-1203 RESISTOR 120.0 1% 0.125W TF TC=0±25 28480 0699-1203 R19 0698-6317 RESISTOR 500 0.1% 0.125W TF TC=0±25 28480 0698-6317...

84 Service Replaceable Parts RP1 1810-1242 1 RESISTOR NETWORK 28480 1810-1242 S1 3101-2609 1 SWITCH-SL DPST STD 5A 250VAC PC 28480 3101-2609 S2 3101-3007 1 SWITCH-6 STATION ASSEMBLY 28480 3101-3007 T1 9100-4750 1 TRANSFORMER-POWER (with mtg. hardware) 28480 9100-4750 U1 1826-1403 2 IC V RGLTER-ADJ-P...

Index 87 Numerics 100x attenuator test , 32 10x attenuator test , 30 A ac adapter , 20 ac coupling adapters , 19 ac low frequency , 55 accessories available to order , 8 circuit connector posts , 15 extension leads , 14 ground leads , 14 mini grabbers , 15 probe tips , 14 shielded signal leads , 15 ...

Agilent TechnologiesP.O. Box 21971900 Garden of the Gods Road Notices © Agilent Technologies, Inc. 2000-2004 No part of this manual may be reproduced in any form or by any means (including electronic storage and retrieval or translation into a foreign language) without prior agreement and written co...

Product Safety Notices This apparatus has been designed and tested in accordance with IEC Publication 1010, 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 po...