Gebruiksaanwijzing /service van het product 1142A van de fabrikant Agilent Technologies
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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 T echnologies 2000-2004 All Rights Re.
2 Agilent T echnologies 1141A Differential Probe and 1142A Probe Contro l and Power Module This manual contains information for use an d service of the differential probe sy stem, the 1141A Differentia l Probe and 1142A Probe Control and Power Module.
Contents 3 1 Operating the Probe Accessories Supplied 6 Accessories Availabl e 8 To inspect the probe 9 Using the probe with other instruments 9 Recommended Test Equipment 9 2 Calibration Tests and Ad.
4 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.
5 1 Operating the Probe.
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 sy stem. Accessories Supplied The following items are supplied as part of the 1141A/1142A probe sy stem.
7 Operating the Probe Accessories Supplied Figure 1-1 1141A Differential Pr obe and Accessories.
8 Operating the Probe Accessories Available Figure 1-2 1141A Miscellaneous Accessories Figure 1-3 1142A Probe Control and Power Module Accessories A vailable The following accessories can be ordered.
9 Operating the Probe T o inspect the probe T o inspect the probe Inspect the shipping container for damage. If the shipping container or cushioning material is damaged, it should be kept unt il t he contents of the shipment have been checked for completeness and the instrume nt had been checked mechanically and electrically .
10 Operating the Probe Recommended T e st Equipment Setting up the probe The following paragraphs cover sy stem preparation and initial adjustments. Power Requirements The 1141A/1142A probe sy stem (specifically the 1142A) require s a power source of either 90 to 132/19 8 to 264 V ac, 47 to 440 Hz, 25 V A maximum.
11 Operating the Probe Recommended T est E quipment WARNING Before connecting this instrument, the protect ive earth terminal of the instrum ent must be connected to the protective conductor of the (Mains) power cord. The Mains plug must be inserted in a socket outlet pr ovided with a protective each contact.
12 Operating the Probe Recommended T e st Equipment • Offset null zeroes the dc level at the output of the probe. The range o f 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.
13 Operating the Probe Recommended T est E quipment 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 supp ly output to 5 V. 7 Arrange a connection between the powe r supply and the tes t board.
14 Operating the Probe Recommended T e st Equipment Figure 1-7 Basic Accessory Connections Probe Tips Probe tips fit into the receptacles in the pr obe 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.
15 Operating the Probe Recommended T est E quipment Note Use extension leads and simi lar connection accessories carefully. Extension leads compromise the high-frequency specificatio ns of the probe. CMRR is particularly sensitive to unbalanced inpu t parameters.
16 Operating the Probe Recommended T e st Equipment Adapters There are three adapters for use with th e differential probe. T wo 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.
17 Operating the Probe Recommended T est E quipment Adapter Combinations The figure below shows the allowed adapt e r and probe connections. There are two specific combinations that should not be used. • Do not attach the ac adapter between an attenuator adap ter and the probe.
18 Operating the Probe Recommended T e st Equipment Connector Compatibility The following are general connector charact eristics for the probe, adapters, and accessories. • The female connectors on the probe, adap ters, and other accessories are designed to mate with 0.
19 Operating the Probe Recommended T est E quipment Probe System Coupling Functions dc Reject dc Reject is the best method of eliminating the dc component of a signal whe n dc is not a factor in the measurement.
20 Operating the Probe Recommended T e st Equipment T o use dc reject: 1 Remove the ac adapter if it is insta lled. 2 On the front panel of the 1142A, press Local. 3 Under DC Reject on the front panel, pr ess 5.0 Hz or 0.5 Hz individually, or 5.0 Hz and 0.
21 Operating the Probe Recommended T est E quipment T o use ac coupling: 1 Attach the ac coupling adapter to the i nput of the probe or the input of the attenuator adapter.
22 Operating the Probe Recommended T e st Equipment Function Select The easiest way to control the function select line s 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 avo id problems with ground loops, they must be electrically isolated.
23 Operating the Probe Recommended T est E quipment Differential Amplifiers and CMRR The 1141A Differential P robe is a high-impedan ce differential amplifier . A characteristic of differential amplifiers is the ability to re ject signals that are common to the two inputs.
24 Operating the Probe Recommended T e st Equipment.
25 2 Calibration T e sts and Adjustment.
26 Calibration T ests and Adjust ment Equipment Required Introduction This chapter is divided into two sections. The first section gives calibration tests and the second ad justment procedures for the 1141A Differential Probe and 1142A Prob e Control and Power Module.
27 Calibration T ests and Adjustment The T est Board Calibration T ests These procedures test the probe’ s electrical performance using applicable specifications given in “Performance Specifi cations and Characteristics” on page 55 as performance standards.
28 Calibration T ests and Adjust ment 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.
29 Calibration T ests and Adjustment dc Gain Accuracy Figure 2-2 2 Set up the 1142A probe control and power modu le as follows: a Set the Local/Remote push button to Local.
30 Calibration T ests and Adjust ment dc Gain Accuracy Figure 2-3 Signal to - input 10 Calculate probe gain a s Record the result of this calcul ation in the “Calibration T est Record” on page 39. T o pass this test, the probe gain = 0.98 to 1.0 2 NOTE Failure of the gain accuracy test can be cause d by mis-adjustment of the probe .
31 Calibration T ests and Adjustment dc Gain Accuracy Figure 2-4 Signal to + input 3 Set the dc calibrator ou tput 3 V dc. 4 Record the V in1 measuremen t from the top DVM in fi gure 2-2.
32 Calibration T ests and Adjust ment dc Gain Accuracy 100x Attenuator Accuracy Test NOTE If the gain test for the probe fail s, it will be reflected in the test for the 100x attenuator adapter. Do not continue until th e probe passes the gain test. 1 Disconnect the probe/attenu ator fr om the test board.
33 Calibration T ests and Adjustment dc Gain Accuracy 6 Carefully connect the inp ut of the probe/att enuator 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 bo ttom DVM in figure 2-2.
34 Calibration T ests and Adjust ment Bandwidth Bandwidth This test checks the high- frequency resp onse of the 1 141A Differential Probe. The bandwidth of the oscilloscope is characteriz ed first so it is not a factor in the measurement.
35 Calibration T ests and Adjustment Bandwidth 6 Reconfigu re the equip ment. 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.
36 Calibration T ests and Adjust ment CMRR T est CMRR T est 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 co nnector to the PR OBE connection on the rear of the 1142A Probe Control and Power Module.
37 Calibration T ests and Adjustment CMRR T est 7 On the oscilloscope, pr ess AUTOSCAL E 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.
38 Calibration T ests and Adjust ment CMRR T est 15 Connect the input of the pr obe to the test board in the posit ion shown in t he figure belo w (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 ).
39 Calibration T ests and Adjustment Calibration T est Re cord Calibration T e st Record 1141A/1142A Differe ntial Probe T ested by_____________ ____________ Serial No.
40 Calibration T ests and Adjust ment Probe Adjustment Adjustments This section provides adjustment proced ures for the 1141A Different ial Probe and attenuator adapters.
41 Calibration T ests and Adjustment Probe Adjustment The following equipment is required for this procedure. Procedur es are bas ed on the model or part number recommended. Equipment Required Probe Preparation The probe c over mu st be remo ved before adjustment.
42 Calibration T ests and Adjust ment Adjustment Procedure 6 As shown in the f igure belo w, use the grounding screw to reinstall the ground block on the P C assembly. Figure 2-13 Attaching Ground Block to Probe PC Assembly The ground block provides a mechanical an d el ectrical connection when the probe PC assembly is connected to the test board.
43 Calibration T ests and Adjustment Adjustment Procedure 3 On the oscilloscope, then press CLEAR DISPLAY. Press AUTO SCALE, then set up the followin g parameters. 4 On the oscilloscope, measure the peak-to- peak voltage of the channel 1 signal and record the reading.
44 Calibration T ests and Adjust ment 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 slo wly so the oscilloscope display has time to react to si gnal averaging.
45 Calibration T ests and Adjustment Adjustment Procedure 2 Change the oscillosc ope sett ings to: 3 Carefully connect the i nput of the prob e to the test boar d in the position sh own in the figure below (signal to + input).
46 Calibration T ests and Adjust ment Adjustment Procedure 5 Carefully connect the probe to the test board in position shown in the figure below (signal to both inpu ts). Figure 2-19 Signal to both inputs 6 Change the func tion generator se ttings to: • Sine wave •4 k H z •1 .
47 Calibration T ests and Adjustment Adjustment Procedure High Frequency Com pensation This adjustment sequence continues fr om the Low Frequency Response and CMRR adjustment. However , it can be done separa tely if the probe meets all specifications except bandwidth.
48 Calibration T ests and Adjust ment Adjustment Procedure 4 Assemble the PC assemb ly in th e top co ver. The side of the PC assembly with the l arge 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 .
49 Calibration T ests and Adjustment Attenuator Adapte r Adjustment Attenuator Adapter Adjustment The following procedure should be used if it is necessary to adjust an attenuator adapter . Attenuator adapters h ave only characteristics; they do not have any spec ifications.
50 Calibration T ests and Adjust ment Attenuator Adapter Adjustme nt Adjustment Procedure NOTE The attenuator must be adjusted when inst alled on the 1141A probe with which it will be used. The specifications and characteristi cs will not be met if the attenuator adapter is adjusted with o ne differentia l probe th en used with another.
51 Calibration T ests and Adjustment Attenuator Adapte r Adjustment 7 Connect the adapter/probe co mbinatio n 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 pul se response, the flattest pulse top.
52 Calibration T ests and Adjust ment Attenuator Adapter Adjustme nt 11 Connect the adapter/probe co mbinatio n to the test board in the position shown in the figure below (sign al to both inputs). Figure 2-25 Signal to both input 12 Alternately adjust the LF CMRR and th en the -HF RESP for a mini mum signal on the oscilloscope.
53 3 Service.
54 Service Introduction Introduction This section provides troubleshooting, servic e, and repair information for the 1141A Differential Probe and 1142 A Probe Control and Power Module. The troubleshooting information is provided to isolate a faulty assembl y .
55 Service Performance Sp ecifications and Ch aracteristics Performance Specifications and Characteristics The following tabl e gives performance specifi cations used to test the 1141A and 1142A. It also gives performance characteristics that are typical for the probe sy stem.
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 input adapters D.
57 Service Performance Sp ecifications and Ch aracteristics Figure 3-2 Maximum Input Voltage vs. Fre quency Legend A. Input voltage limits for probe alone.
58 Service General Characteristics General Characteristics The following characterist ics apply to the 11 41A Differential Probe with the 1142A Probe Control and Power Module.
59 Service Theory of Operation Theory of Operation The following dis cussion covers block-le vel theory for the 1141A/1142A differential probe sy stem. Refer to the block diagram below . The differential probe s y stem co nsists of two units, the 1141A Different ial Probe with its accessories and the 1142A Probe Control and Power Module.
60 Service Theory of Operation Differential Probe The probe contains a two-path differential am plifier with unity gain. It is implemented on a double-sided surface-mount PC board with the high-frequen cy path on one side and the low-frequency path on the other .
61 Service Theory of Operation Offset Functions There are two offset functions developed in the control module: var iable 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 U 8 and selected by multiplexer U3 as the inpu t to offset amp U7 .
62 Service Theory of Operation Te s t B o a r d The test board is a device for conveniently connecting test signals to the differential probe. The probe can be connected to the boar d with the signal t o the positive, negative, or both inputs.
63 Service Service Policy Service Policy For parts of the 1141A/114 2A probe sy stem th at are complex, the service policy is for assembly-level repair . For parts of the sy stem with simple circuitry , the service policy is component-level repair . The service policy for the 1141A Differential Probe is assembly-level repair .
64 Service T roubleshoo ting T roubleshooting Use the followi ng paragraphs to assist i n troubleshooting problems with the 1141A/1142A Differential Probe. Probe T roubleshooting T o troubleshoot the probe: 1 Apply a known sign al to the input o f the probe.
65 Service T roubleshooti ng Figure 3-7 1142A Probe Control and Power Module.
66 Service Removing and Replacin g Assemblies Removing and Replacing Assemblies This section contains proce dures for the removal and repl acement of major assemblies. CAUTION Never remove or install any assembly wi th the instrument power ON. Component damage can occur.
67 Service Removing and Replac ing 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 an d put them on the new one.
68 Service Removing and Replacin g Assemblies CAUTION 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 botto m cover is closed, part of it will pinch wires that are laying o ver these areas.
69 Service Removing and Replac ing Assemblies 2 Combine the thumbwheel scre w and thumbwheel and inse rt them into the hole in the outer housing. 3 Insert the sub strate/board into the outer housi ng. Slip the at tenuator ground (attenuator adapters only ) over the thumbwheel screw and seat the input connectors in the proper holes in the housing.
70 Service Removing and Replacin g Assemblies Probe Control and Power Module Use the following procedure to disassemb le the p robe control an d power modu le. WARNING Hazardous voltages exist on the power supply. To avoid electrical shock, adhere closely to the followin g procedures.
71 Service Replaceable Parts Replaceable Parts This section contains information fo r ordering parts. Service support for the 1141A Differential Probe is to the assembly level. Se rvice support for the adapters is as complete assemblies, except for the probe tip caps a nd the probe tips.
72 Service Replaceable Parts Mail order forms and specific ordering in formation are available through your local Agilent T echnologies Sales Office. Addresse s and telephone numbers are located in a separate document shipped with the manuals. Manufacturers’ Codes A list of manufacturers’ codes is given t he table below .
73 Service Replaceable Parts Exploded V iew Figure 3-11 1141A Differential Probe Parts.
74 Service Replaceable Parts Figure 3-12 Power and Control Boar d Component Locato r.
75 Service Replaceable Parts Figure 3-13 Cabling Diagram.
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.
77 Service Replaceable Parts Figure 3-15 1142A Probe Control and Power Module.
78 Service Replaceable Parts 1141A and 1142A R eplaceable Parts Ref. Des. Part Number Qty Description Mfr. Code Mfr. Part Number 1141A Differential Probe A1 01141-665 03 1 PC ASSEMBLY-DIFFE RENTIAL PR.
79 Service Replaceable Parts A1 01142-665 01 1 P C 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.
80 Service Replaceable Parts Power Supply Replac eable Parts Ref. Des. Part Number Qty Description Mfr. Code Mfr. Part Number Prefix the reference designators with A1 C1 0160-61 90 2 CAPACITOR -FXD 0.33UF ±10% 50 VDC 28480 0160-6190 C2 0160-5474 1 CAPACITOR-FXD 0.
81 Service Replaceable Parts CR1 NOT ASSIGNED CR2 1901-1087 2 DIODE-PWR RECT 100V 3A 04713 M R501 CR3 1901-1087 DI ODE-PWR RECT 100V 3A 04713 MR501 CR4 NOT ASSIGNED CR5 1901-0731 8 DIODE-PWR RECT 400V.
82 Service Replaceable Parts J1 1252-47 31 1 CONNECTOR-AC PWR 28480 1251-4743 J2 1252-1487 1 CONN-RECT D-SUBMIN 9-CKT (remote ) 28480 1252-1487 J3 1252-3935 1 CONNECTOR-ROUND 8-CKT (probe) 28480 1252-3134 MP1 14 00-1604 1 LED MOUNT 28480 1400-1604 MP2 12 05-0732 4 SP RING CLIP 28480 1205-0732 MP3 03 61-0685 3 RIVET-BLI ND DR-PIN RNDH 0.
83 Service Replaceable Parts R16 0698-6317 2 RESIS TOR 500 0.1% 0.125W TF TC=0±25 28480 0698-6317 R17 0698-4002 RESISTOR 5K 1% 0.125W TF TC=0±10 0 24546 CT4-1/8-TO-5001-F R18 0699-1203 RESISTOR 120.0 1% 0.125W TF TC=0±2 5 28480 0699-1203 R19 0698-6317 RESISTOR 500 0.
84 Service Replaceable Parts RP1 1810-1242 1 RESISTOR NETWOR K 28480 1810-1242 S1 3101-2609 1 SWITCH-SL DPST STD 5A 250VAC P C 28480 3101-2609 S2 3101-3007 1 SWITCH-6 STATION ASSEMBLY 28480 3101-3007 T1 9100-4750 1 TRANSFORMER-POWER ( with mtg.
85 Service Replaceable Parts Locator T able for Control a nd Power Supply Ref. Des. Grid Loc Ref Des Grid Loc Ref Des Grid Loc Ref Des Grid Loc Ref Des Grid Loc Ref Des Grid Loc Ref Des Grid Loc Ref D.
86 Service Replaceable Parts.
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 e.
Index 88 M making measurem ents , 13 manufacturer’ s code s , 72 maximum input voltage , 55 mini grabbers , 15 N noises , 55 O offset , 20 offset functions , 61 offset null , 11 operating environmen.
Agilent T echnologies P .O. Box 2197 1900 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 consent from Agilent Technologies, Inc.
Product Safety Notices This apparatus has been designed and tested in accorda nce with IEC Publication 1010, Sa fety Requirements for Measuring Apparatus, and ha s been supplied in a safe condition. This is a Safety Class I instrument (provided with t erminal for protective earthing).
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