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HP 5501B Operating And Service Manual

Laser head.
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Title & Document Type:
Manual Part Number:
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Revision Date:
This manual may contain references to HP or Hewlett-Packard. Please note that Hewlett-
Packard's former test and measurement, semiconductor products and chemical analysis
businesses are now part of Agilent Technologies.
No changes have been made to this manual, with the exception of correcting the odd
spelling and grammatical errors. In some places original photographs may be replaced
or augmented with modern digital photographs. (it's weird looking at an old BW HP
manual and seeing a color photograph... still gets me)
This manual is reproduced from high-resolution scans of an original document, which
was then converted to Word format using custom designed OCR software for my
personal use.
This means that what you see here is not a scan of a scan/copy.
OCR errors may exist and as such the user of this document should take care and use
common sense when referencing this documentation.
This documentation is © Copyright 1980 Hewlett Packard and © Copyright 2006, Jack Hudler,
Permission to use and redistribute this documentation for non-commercial and internal corporate
purposes is hereby granted, free of charge.
Any redistribution of this documentation or its derivates must include this copyright notice.
You may not sell this documentation or its derivations without written consent.
You may modify this documentation as necessary, but you may not sell derivative works based
on it.
You may include this documentation with the equipment/hardware on which it is used for the
purposes of selling the equipment/hardware. If you advertise that a copy of this documentation is
included in the sale, you must state that is for "Free".
Meaning if you want to gratuitously toss in a copy of the manual on an eBay sale, it's ok with me
as long as you state it's for free. No you can't sell a digital archive of manuals and say it includes
a free copy of this documentation. You must give it away with equipment.
I think you get the spirit of the copyright; it takes a lot of hours to scan and replicate a manual. I
just want this used in the spirit in which is it given.
Agilent if you have questions or wish to include this in your archive email me.
HP5501B Laser Head Operating & Service Manual
September 1986
HP References in this Manual
Changes to this Manual
About this Manual
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   Summary of Contents for HP 5501B

  • Page 1

    No changes have been made to this manual, with the exception of correcting the odd spelling and grammatical errors. In some places original photographs may be replaced or augmented with modern digital photographs. (it’s weird looking at an old BW HP manual and seeing a color photograph… still gets me)

  • Page 3

    OPERATING AND SERVICE MANUAL HP5501B LASER HEAD SERIAL NUMBER PREFIX: 2632A This manual applies directly to HP5501B Laser Heads with serial numbers prefixed 2632A. Lower number serial prefixes are covered in Section 7 while higher number serial prefixes are documented with "Manual Changes" Supplements described in Section 7.

  • Page 4


  • Page 5


  • Page 6

    Devices and Radiological Health regulations 21 CFR 1040.10 and 1040.11. These regulations may also apply to the end product into which the 5501B will be designed. Care must be taken to insure that the end product complies with all applicable national and local laser safety regulations.

  • Page 7: Table Of Contents

    HP5501B LASER HEAD REAR PANEL INDICATORS AND CONNECTORS ......3-11 3-10. OPERATING MODES ......................3-13 3-12. Warmup Time Operating Notes .....................3-14 3-13. HP 10740A Coupler Based Systems - Manual Monitoring ............3-14 3-14. Systems with HP10745A or HP10746A Cards - Automatic Monitoring .........3-14 3-16. HP10740A Coupler - Error Signal Information...............3-14 3-17.

  • Page 8: Table Of Contents

    Table of Contents ADJUSTMENTS............................5-1 5-1. Introduction ..........................5-1 5-3. Safety Considerations ......................5-1 5-5. Recommended test equipment ....................5-1 5-7. Factory Selected Components ....................5-1 5-9. Adjustment Procedures......................5-2 5-11. Reference Temperature Adjustments ..................5-2 5-14. Preliminary Procedure......................5-2 5-17. Laser Tube Current Adjustment ....................5-4 REPLACEABLE PARTS ........................6-1 6-1.

  • Page 9: Table Of Contents

    Table of Contents 8-97. Dividers Ⓑ..........................8-32 8-99. State Machine Ⓕ........................8-33 8-105. Liquid Crystal Ⓓ........................8-34 8-109. Photodiode and Amplifier Ⓔ....................8-34 8-111. Warmup Error Amplifier and Comparator Ⓙ .................8-34 8-114. Subtracting Sample and Hold Ⓗ ...................8-34 8-118. A1/A3 Power Amplifier Ⓘ .......................8-35 8-121.

  • Page 10: Table Of Contents

    Figure 2-2. HP 107798 Reference Cable ......................2-4 Figure 2-3. Typical Transducer System Interconnections................2-5 Figure 2-4. Interconnecting Plug Details ......................2-5 Figure 2-5. HP 5501B Laser Head Interconnect Wire Fabrication ...............2-6 Figure 2-6. Mounting Details and Physical Characteristics ................2-8 Figure 3-1. HP5501B Front Panel Controls ....................3-10 Figure 3-2.

  • Page 11: Table Of Contents

    Table 1-2. Recommended Test Equipment....................1-6 Table 2-1. Laser Head System Signal Chart....................2-6 Table 2-2. HP 5501B Power Supply Requirements..................2-7 Table 3-1. Proper 55018 Rear Panel LED Power-up Sequence..............3-13 Table 3-1. Program Modifications for Table 4-12 in the HP5501A System Manual ........3-16 Table 3-2.

  • Page 13: Figure 1-1 Hp5501b Laser Head

    HP5501B Installation Figure 1-1 HP5501B Laser Head...

  • Page 14: General Information, Equipment Description

    1-3. The HP part number of this manual is listed on the title page. Also listed is a microfiche part number for ordering 4 X 6" microfilm transparencies of this manual. The microfiche package also includes the latest "Manual Changes" supplement and any pertinent Service Notes.

  • Page 15: Manual Organization

    SECTION 6, REPLACEABLE PARTS: includes Tables of Replaceable Parts including illustrated parts breakdowns of chassis and mechanical assemblies, Abbreviations, Ordering Information, and the HP Direct Mail Order System. SECTION 7, MANUAL CHANGES: describes how to update or backdate the manual for prefixes other than those listed on the title page.

  • Page 16: Safety Considerations

    1-16. Equipment Supplied 1-17. The HP5501B Laser Head is supplied with a test polarizer and two 4-pin connectors for use in fabricating the power and reference cables. The HP Part Numbers for the three items are: Test Polarizer 1000-0616 Reference Signal Connector (P1)

  • Page 17: Specifications

    HP5501B Installation 1-20. Specifications 1-21. Table 1-1 lists the specifications and performance characteristics for the HP5501B Laser Head. Table 1-1. HP5501B Laser Head Specifications and Performance Characteristics Description: The HP5501B Laser Head contains an automatically tuned Helium-Neon laser, circuits to control the laser, and a reference optical receiver.

  • Page 18: Recommended Test Equipment

    Equivalent Characteristics May Be Substituted) Signature Detect TTL level signals HP 5005A/B Multimeter Oscilloscope 100 MHz Bandwidth HP 1740A (if available) Laser Power Range: 1 microwatt to 1 milliwatt United Detector Technology Meter Accuracy: ±10% Model 351L Clip-on T,A 10 ma range accuracy ±0.1 ma...

  • Page 19

    HP's option without waiting for a claim settlement. 2-7. Warranty Claims 2-8. Contact the nearest HP Sales and Support Office (see list at the end of this manual) for information relative to warranty claims. 2-9. Laser Tube Shipment NOTE The laser tube assembly MUST be shipped in an approved HP container.

  • Page 20: Tagging For Service

    2-12. If the instrument is being returned to Hewlett-Packard for service, please complete one of the blue repair tags (HP Part Number 9320-3896) located at the end of this manual and attaches it to the instrument. 2-13. Packaging for Reshipment 1.

  • Page 21

    HP5501B Installation 10778B LENGTH 10 METRES (32.8 FT) Figure 2-1. HP 10778B Power Cable...

  • Page 22

    HP5501B Installation 10779B LENGTH 10 METRES (32.8 FT) Figure 2-2. HP 10779B Reference Cable...

  • Page 23: Power And Signal Connections

    Table 2-1 for rear-panel connector pin numbers of all available power and signal lines. PLUG CABLE DESCRIPTION REFERENCE SIGNAL HP 10779B or Dual coax; two #22 power wires. HP Part No. 1251-3450 equivalent Everything enclosed by a second insulated shield. POWER HP 10778B or Three # 20 wires HP Part No. 1251-3447 equivalent Figure 2-4.

  • Page 24: Figure 2-5. Hp 5501b Laser Head Interconnect Wire Fabrication


  • Page 25: Grounding Considerations

    Table 2-2 lists the supply voltages, currents, and tolerances required by the HP5501B Laser Head. Note that other components of the system also use ±15 Volts. Add these to the laser head current requirements to obtain the overall system requirements. Table 2-2. HP 5501B Power Supply Requirements Supply Voltage Tolerance...

  • Page 26: Dimensions

    HP5501B Installation 2-31. Dimensions 2-32. Figure 2-6 shows the HP5501B Laser Head dimensions. DIMENSIONS IN MILLIMETERS Figure 2-6. Mounting Details and Physical Characteristics...

  • Page 27: Mounting And Fixturing

    HP5501B Installation 2-33. Mounting and Fixturing 2-34. Heat Flow Considerations. The laser tuning technique of the HP5501B requires efficient heat exchange with the ambient. Heat flow is primarily through the base of the laser head assembly to the surrounding environment. An external heat sink is not required but free air circulation around the laser head will ensure good performance.

  • Page 28

    HP5501B Operation 3 OPERATION 3-1. Introduction 3-2. This section provides operating information for the HP5501B Laser Head. Included are operation features of the instrument's front and rear panel controls and connectors. Also provided is supplemental operating information for HP5501A Laser Transducer Systems equipped with HP5501B Laser Heads.

  • Page 29: Hp5501b Laser Head Rear Panel Indicators And Connectors

    HP5501B Operation 3-8. HP5501B LASER HEAD REAR PANEL INDICATORS AND CONNECTORS NOTE A TILDE ("~") PRECEDING A SIGNAL NAME INDICATES NEGATIVE- TRUE LOGIC LEVELS. 3-9. Following are descriptions of the HP5501B rear panel features shown in Figure 3-2. +15V SUPPLY LED lights if the ±15V input voltages are unbalanced UNBALANCE in the positive direction by one Volt or more.

  • Page 30: Figure 3-2. Hp5501b Rear Panel Connectors And Indicators (continued)

    HP5501B Operation +15V FUSE OPEN RED LED LED lights if +15 Vdc fuse opens. -15V FUSE OPEN RED LED LED lights if -15 Vdc fuse opens. +15V POWER ON GREEN LED LED lights when +15 Vdc power is applied to the HP5501B. -15V POWER ON GREEN LED LED lights when -15 Vdc power is applied to...

  • Page 31: Operating Modes

    HP5501B Operation 3-10. OPERATING MODES 3-11. When power is applied to the HP5501B, an internal state machine resets the laser head to a warmup mode. This mode is used to establish the initial operating temperature of a glass rod that controls the laser cavity length. When this temperature is reached, the state machine switches to an optical tuning mode.

  • Page 32: Warmup Time Operating Notes

    Systems with these cards can use the system computer and software to monitor the laser head warmup. Before describing the software, it will be helpful to examine some background information on the HP10740A Coupler, HP10745A HP-IB Interface, and HP10746A Binary Interface.

  • Page 33: Hp10746a Error Signal Processing

    Tables 4-12 and 4-13 of the HP5501A Laser Transducer Operating and Service Manual, HP Part Number 05501-90028. If desired, some form of time-out algorithm can be added to check if the HP5501B warms up within 10 minutes.

  • Page 34: Table 3-1. Program Modifications For Table 4-12 In The Hp5501a System Manual

    HP5501B Operation Table 3-1. Program Modifications for Table 4-12 in the HP5501A System Manual Branch to subroutine to monitor laser 0: gsb "warmup" status Send Device Clear: Send Remote Enable 38: "warmup":clr 7; rem 7 Send 10740A Backplane reset preset x- 39: wrt 709,"0O0X"...

  • Page 35: Table 3-2. Program Modifications For Table 4-13 In The Hp5501a System Manual

    HP5501B Operation Table 3-2. Program Modifications for Table 4-13 in the HP5501A System Manual Branch to warmup subroutine monitor laser status 0: gsb "warmup" System reset 10746A in 16 bit mode 66: "warmup":wtb 2,0,0,0 1 = simultaneous sample 67: wtb 2,1,130, 3 130 = transfer X Comparator Counter contents to 10746A 3 = prepare for output to host computer...

  • Page 36: Table 3-3. Modified Hp10745a Hp-ib Interface Program

    HP5501B Operation Table 3-3. Modified HP10745A HP-IB Interface Program 0: gsb "warmup" 1: wrt 709,"0O6X" 2: wrt 709,"2V3O" 3: red 709,C 4: 0→E 5: "loop": E+1→E; if E=10;gto -3 wrt709,"1O2X3O" red 709,X if rds(7)<128;gto +2 0→A; gsb "status" (X-16)*6.23023e-6*C→X fmt 1,f12.6 dsp X 13: gto "loop"...

  • Page 37: Table 3-4 Modified Hp10746a Binary Interface Program

    HP5501B Operation Table 3-4 Modified HP10746A Binary Interface Program 0: gsb "warmup" 1: wtb 2,0,0,0,98,3 2: gsb "in" 3: B→C 4: ent "X TOLERANCE IN MICRONS?",r1 5: ent "Y TOLERANCE IN MICRONS?",r2 6: "newdest":0→X;ent "X DESTINATION IN MM?",X 7: 0→Y;ent "Y DESTINATION IN MM?",Y 8: "comp":wtb 2,98,3 9: gsb "in"...

  • Page 38

    HP5501B Operation 62: "prterr": if F=0;prt "X-AXIS ERROR" 63: if F=1;prt "Y-AXIS ERROR" 64: dsp "GO TO GAGE";stp 65: gto 0 66: "warmup":wtb 2,0,0,0 67: wtb 2,1,130,3 68: rdb(2)→B;if B<0;65536+E→B 69: if B<61440;ret 70: int(B/256)-240→B;15-B→B 71: if B>=S;B-S→B 72: if B>=4;B-4→B 73: if B>=2;dsp "LASER NOT READY"...

  • Page 39: Performance Tests

    HP5501B Performance Tests 4 PERFORMANCE TESTS 4-1. Introduction 4-2. This section contains a performance test for the HP5501B Laser Head. A test record is included to record test results for future comparison. 4-3. RECOMMENDED TEST EQUIPMENT 4-4. Test equipment requirements are included in the following procedure. Detailed critical specifications for the required test equipment are contained in Table 1-2, Recommended Test Equipment.

  • Page 40: Figure 4-1. Hp5501b Power Connection

    HP5501B Performance Tests 4-13. Procedure Connect the HP5501B to the HP5501A system (or any suitable dual DC voltage power supply such as the HP6255A) using HP10778B Power Cable as shown in Figure 4-1. HP5501B Power Connection On the HP5501B, set the exit shutter of the turret assembly to its open aperture position.

  • Page 41

    HP5501B Adjustments 5 ADJUSTMENTS 5-1. Introduction 5-2. This section describes adjustments and checks required to return the HP5501B Laser Head to peak operating capabilities when repairs have been made. Included in this section are the test equipment required, equipment setups, and procedures to perform the adjustments. 5-3.

  • Page 42: Adjustment Procedures

    21 to 25°C (69.8 to 77.0°F). 5-13. Test Equipment Required. The reference temperature adjustment requires the following test equipment: Digital Voltmeter, HP Model 3435A 5-14. Preliminary Procedure 5-15. This adjustment must be made with the laser tube at room temperature. If the laser High Voltage Power Supply (A2) or heater has been on, allow at least two hours with ±15 Volts off before...

  • Page 43: Figure 5-2. A3 Controller/ref Board, Jumpers, Test Points, And Adjustment Locations

    HP5501B Adjustments On A3, change the HEATER jumper from NRM to OFF. See Figure 5-2. Apply power to the Digital Voltmeter and set its controls to the 1 Volt DC range. Connect the positive lead of the Digital Voltmeter to A3TP11 then connect the negative lead to A3TP1.

  • Page 44: Laser Tube Current Adjustment

    This procedure adjusts the laser tube current to 3.5 milliamperes ± 0.1 milliampere. Test Equipment Required. The laser current adjustment requires the following test equipment: Clip-On DC Milliammeter, HP Model 428B 5-19. Procedure to adjust the laser tube current, observe the safety precautions in Paragraph 5-4 and proceed as follows: Turn the system power supplies OFF.

  • Page 45: Figure 5-3. 55018 High Voltage Areas And Anode Lead

    HP5501B Adjustments Apply power to the system power supplies. NOTE READY LED will flash rapidly for about 5 seconds. LASER LED illuminates followed almost immediately by emission of laser light. Adjust A1R12 (Figure 5-1) for 3.5 milliamperes ± 0.1 milliampere. If the current cannot be adjusted to this value, see Laser High Voltage Troubleshooting in Section 8.

  • Page 47

    For this reason, assemblies required for on-site spare parts stock must be ordered by the "New Assembly" part number. Table 6-1. Exchange Assemblies New Assembly Exchange Assembly Assembly HP Part No. HP Part No. HP Part No. Laser Assembly 05501-60102 05501-60202 05501-69102 6-6.

  • Page 48: Direct Mail Order System

    No invoices - to provide these advantages, a check or money order must accompany each order. 6-13. Mail order forms and specific ordering information are available through your local HP office. Addresses and phone numbers are located at the back of this manual.

  • Page 49: Table 6-2. Reference Designations And Abbreviations

    HP5501B Replaceable Parts Table 6-2. Reference Designations and Abbreviations REFERENCE DESIGNATIONS = assembly = fuse = miscellaneous mechanical part = thermocouple = attenuator; isolator; termination = filter = electrical connector (movable = test point = fan; motor = hardware portion); plug = integrated circuit;...

  • Page 50: Table 6-3. Hp5501b Board Assemblies Replaceable Parts

    HP5501B Replaceable Parts Table 6-3. HP5501B Board Assemblies Replaceable Parts Reference HP Part Description Mfr Part Number Designation Number Code 05501-60028 0 1 CONNECTOR BOARD ASSEMBLY 28480 05501-60028 SERIES 2632, REVISION A A1C1 0160-4557 0 2 CAPACITOR-FXD .1UF ±20% 50VDC CER...

  • Page 51: Table 6-3. Hp5501b Board Assemblies Replaceable Parts (continued)

    HP5501B Replaceable Parts Table 6-3. HP5501B Board Assemblies Replaceable Parts (Continued) Reference HP Part Description Mfr Part Number Designation Number Code A1R16 0757-0278 RESISTOR 1.78K 1% 1/8W F TC=0±100 24546 CT4-1/8-T0-1781-F A1R17 0757-0278 RESISTOR 1.78K 1% 1/8W F TC=0±100 24546 CT4-1/8-T0-1781-F...

  • Page 52

    HP5501B Replaceable Parts Table 6-3. HP5501B Board Assemblies Replaceable Parts (Continued) Reference HP Part Description Mfr Part Number Designation Number Code 05501-60027 9 1 CONTROLLER/REFERENCE BOARD ASSEMBLY 28480 05501-60027 SERIES 2632. REVISION A A3C1 0180-2929 8 1 CAPACITOR-FXD 68UF±10% 10VDC TA...

  • Page 53

    HP5501B Replaceable Parts Table 6-3. HP5501B Board Assemblies Replaceable Parts (Continued) Reference HP Part Description Mfr Part Number Designation Number Code A3JMP6 1251-4813 CONNECTOR 5-PIN M POST TYPE 28480 1251 4813 A3JMP7 1251-4047 CONNECTOR 3-PIN M POST TYPE 28480 1251-4047...

  • Page 54

    HP5501B Replaceable Parts Table 6-3. HP5501B Board Assemblies Replaceable Parts (Continued) Reference HP Part Description Mfr Part Number Designation Number Code A3R63 0698-0084 RESISTOR 2.15K 1% 1/8W F TC=0±100 24546 CT4-1/8-T0-2151-F A3R64 1810-0374 NETWORK-RES 8-SIP 1. OK OHM X 4...

  • Page 55

    HP5501B Replaceable Parts Table 6-3. HP5501B Board Assemblies Replaceable Parts (Continued) Reference HP Part Description Mfr Part Number Designation Number Code 05501-60029 1 1 SAMPLER BOARD ASSEMBLY 28480 05501-60029 SERIES 2632. REVISION B A4CR1 1990-0770 1 1 PHOTODIODE ID=30NA-MAX 32694 OP 913 (SELECTED)

  • Page 56: Table 6-3. Hp5501b Miscellaneous Chassis Parts (continued)

    28480 1000-0616 LABELS AND NAMEPLATES 05501-80011 3 1 NAMEPLATE 28480 05501-80011 5080-0098 1 1 LABEL-SERIAL NO. 28480 5080-0098 7120-2444 3 1 LABEL-5501B LASER 28480 7120-2444 7120-3731 3 2 LABEL-HIGH VOLTAGE WARNING 28480 7120-3731 7120-5180 0 1 LABEL-WARNING 28480 7120-5180 7121-1650...

  • Page 57: Exploded View

    HP5501B Replaceable Parts 6-14. Exploded View Figure 6-1. HP5501B Laser Head Exploded View 6-11...

  • Page 58: Table 6-4. Manufacturer's Code List

    HP5501B Replaceable Parts Table 6-4. Manufacturer's Code List Manufacturer Name Address Zip Code Code 00000 ANY SATISFACTORY SUPPLIER 01295 TEXAS INSTRUMENTS INC DALLAS TX US 75265 03508 GE CO SEMICONDUCTOR PROD DEPT AUBURN NY US 13201 04713 MOTOROLA INC SEMI-COND PROD PHOENIX AZ US 85008...

  • Page 59

    If any of the instruments shipped with the system have a higher serial number than those listed on the title page and the" Manual Changes" sheet does not cover the prefix, contact your local HP Sales and Service Office for information.

  • Page 61: Service

    HP5501B Service 8 SERVICE 8-1. Introduction 8-2. This section contains service information for the HP5501B Laser Head. Also included are safety considerations, theory of operation, block diagrams, schematic diagrams, component locators, and troubleshooting and repair procedures. Other useful service information also provided in other sections of this manual include: performance tests in Section 4, adjustments in...

  • Page 62: Figure 8-1. Schematic Diagram Notes

    HP5501B Service Figure 8-1. Schematic Diagram Notes...

  • Page 63

    HP5501B Service 8-12. Safety Considerations 8-13. The following paragraphs contain warnings and cautions that must be followed for your protection and to avoid damage to the equipment. MAINTENANCE DESCRIBED HEREIN PERFORMED WITH POWER SUPPLIED EQUIPMENT WITH PROTECTIVE COVERS REMOVED. SUCH MAINTENANCE SHOULD BE PERFORMED ONLY BY SERVICE-TRAINED PERSONNEL WHO ARE AWARE OF THE HAZARDS INVOLVED (FOR EXAMPLE, FIRE AND ELECTRIC SHOCK).

  • Page 64

    HP5501B Service 8-14. Safety Symbols 8-15. The following safety symbols are used on the instrument or in this manual. Instruction manual symbol. The product will be marked with this symbol when it is necessary for the user to refer to the instruction manual in order to prevent damage to the instrument.

  • Page 65

    Collimating minimizes variations in the diameter of the beam as it travels away from the laser head. Laser frequency F2 is polarized in a plane parallel to the base of the HP 5501B chassis. The other laser frequency F1 is polarized perpendicular to F2. The difference between the two laser frequencies F1 and F2 is small compared to their optical frequencies.

  • Page 66: Figure 8-2.hp5501b Laser Head Block Diagram

    HP5501B Service Figure 8-2.HP5501B Laser Head Block Diagram...

  • Page 67: Figure 8-3. Flow Diagram For State Machine

    The cavity length is determined by the separation of two mirrors that are held against the ends of a glass rod. The HP 55018 uses a thermal tuning technique to control the cavity length. Cavity length increases when the rod is heated and decreases when it cools.

  • Page 68: Figure 8-4. Feedback Loop During Warmup Mode

    HP5501B Service 8-31. The heater coil is used both to heat the rod and to sense its temperature. For 2.56 seconds (nominal) out of every 25.6 seconds (nominal) of the warmup cycle (see Figure 8-5), the state machine disables the power amplifier and the heater allowing the heater coil to stabilize to the rod temperature.

  • Page 69: Figure 8-5. Warmup Mode Timing Diagram

    HP5501B Service Figure 8-5. Warmup Mode Timing Diagram 8-34. Optical Mode Tuning 8-35. In optical mode, the state machine switches the subtracting sample and hold inputs from warmup feedback to optical feedback as shown in Figure 8-6. The optical mode feedback controls the laser cavity length by measuring and comparing the power of the two laser frequency components.

  • Page 70: Figure 8-7. A6 Sampler Assembly, Exploded View

    HP5501B Service 8-36. The power in each laser frequency component is measured by sampling some of the laser light with a pair of non-polarizing beam splitters (see Figure 8-7) and passing one of the laser frequency components, then the other, through an optical switch and onto a photodiode. The beam splitters are part of the A6 Sampler Assembly and the photodiode is mounted on the A4 Sampler Board.

  • Page 71: Figure 8-8. Liquid Crystal Timing Diagram (optical Mode)

    HP5501B Service 8-37. When the state machine excites the liquid crystal into its active state (see Figure 8-8), the laser beam passes through the liquid crystal unaltered. The polarizer blocks the horizontal component and passes the vertical component onto the photodiode. The photodiode current is proportional to the power in the vertical component and is amplified and converted to a voltage by the photodiode amplifier.

  • Page 72

    HP5501B Service 8-40. Laser Assembly Optics 8-41. The laser assembly optics ensures correct laser frequency polarizations and also collimates the laser beam. When the laser beam leaves the laser assembly, the horizontal component is polarized parallel to the base of the HP5501B. The vertical component is polarized perpendicular to the horizontal component.

  • Page 73: Table 8-1. A3 U9 Test Ic Signal Summary

    HP5501B Service 8-49. BUILT-IN TEST AIDS 8-50. Several jumpers are included to aid in testing. The RESET jumper, JMP1, places the state machine in a repetitive mode to allow signature measurements. The ~REF ON jumper, JMP2, sets the ~REF ON signal so that U17 cannot influence the state machine. LIQ CRYS jumper, JMP3, places the liquid crystal in either the active or passive state.

  • Page 74: Figure 8-9. Logic Clip Monitoring Of Test Ic U9

    HP5501B Service Figure 8-9. Logic Clip Monitoring of Test IC U9 8-52. ASSEMBLY REMOVAL INSTRUCTIONS 8-53. Figure 6-1, the exploded view diagram in Section 6, shows the HP5501B assembly locations, provides access and removal information, and gives assembly part number references. 8-54.

  • Page 75

    HP5501B Service 8-55. To remove the front panel and side covers from the laser head, perform the following procedure: Remove ±15 Volt power from HP5501B Laser Head. Rotate the front-panel turret so that the large opening is at the bottom and the slotted, 1/4-turn fastener is visible through the opening.

  • Page 76: Figure 8-10. Hp5501b Front Panel And Side Cover Removal

    HP5501B Service Figure 8-10. HP5501B Front Panel and Side Cover Removal 8-56. To remove the A1 Connector Board Assembly from the HP5501B chassis, perform the following procedure. Remove ±15 Volt power from HP5501B Laser Head. Remove front panel and side covers as described in paragraph 8-55. Remove two Pozidriv screws (H7) that secure rear panel (MP4) to laser base (MP2).

  • Page 77

    HP5501B Service Disconnect A2 High Voltage Power Supply and A5 Laser Assembly cabling from A1 Connector Board. These wires connect to A1J3 and A1J4 respectively. Remove A1 Connector Board Assembly. To install the A1 Connector board Assembly, perform the reverse of the removal procedure.

  • Page 78: Figure 8-11. Factory-adjusted Sampler Mount (mp1)

    Sampler Mount to the shield (MP10). Figure 8-11. Factory-adjusted Sampler Mount (MP1) 8-60. To remove the A5 Laser Assembly (HP Part No. 05501-60102) from the HP5501B chassis, perform the following procedure. Remove ±15 Volt power from HP5501B Laser Head.

  • Page 79: Figure 8-12. Laser Tube Tuning Characteristics

    HP5501B Service Remove four Pozidriv screws (H10) that secure A1 Connector board to rear panel assembly (MP4). With rear of laser head facing you, tilt the top edge of the A1 assembly toward you. This will give ample clearance to remove the laser assembly. Remove two Pozidriv screws (H8) from laser base.

  • Page 80: Figure 8-13. Quick Tuning Check Test Setup

    HP5501B Service 8-65. This procedure consists of monitoring test point TP16 on A3 with an oscilloscope to determine the relative amplitudes of F1 and F2 with the heater turned off. If the sampler, photodiode, and amplifier are functioning properly and the heater is turned off, the traces on the oscilloscope will show switching to different levels as it monitors the sampling of F1 and F2.

  • Page 81: Figure 8-14. Quick Tuning Check Waveform Display

    The following material and test equipment is required for the test: A white piece of cardboard. 50 Hz Square Wave Generator (TTL Level) Test Polarizer (HP Part Number 1000-0616) 8-69. To test the liquid crystal, proceed as follows: Remove the liquid crystal from the sampler assembly as shown in Figure 8-15 below: Figure 8-15.

  • Page 82: Figure 8-16. Liquid Crystal Test Setup

    Figure 8-16 and observe the window area; it should go from light to dark while probing the device. A faint change of color or no change indicates a faulty liquid crystal. The replacement HP part number for the liquid crystal is 1990-0768. 8-22...

  • Page 83: Figure 8-17. Hp5501b Test-norm Switch A1s2

    Before HP5501B trouble isolation is attempted; the Laser Head Block Diagram Description (paragraphs 8-18 through 8-45) should be read. All electronic tests can be performed using an HP 5005A/B Signature Multimeter. WITH THE HP5501B COVERS REMOVED AND A1S2 SET TO THE...

  • Page 84

    REFERENCE SIGNAL connector. Otherwise proceed with step d of this procedure. If the failure mode occurs after the 5501B has reached the optical tuning mode (normal operation), skip steps d through k of this procedure. Steps d through k address failures that prevent the laser from reaching stable tuning.

  • Page 85

    HP5501B Service READY LED (green) blinks within 6 minutes, blinks for less than approximately 150 seconds, goes off, and then repeats this action. This indicates that the warmup mode feedback is not properly controlling the heater voltage. Check the following procedures: •...

  • Page 86: Table 8-2. Dc Unbalanced Failures

    HP5501B Service 8-73. A1 CONNECTOR BOARD CIRCUIT THEORY 8-74. The A1 Connector Board interconnects the main laser cable, laser tube heater and power amp, laser power supply, and the A3 Controller/Reference Board. The schematic diagram for A1 is shown in Figure 8-23. Additional information covering heater power amp control circuitry can be found in paragraph 8-119.

  • Page 87

    Remove HP5501B instrument covers as described in paragraph 8-55. Leave TEST-NORM switch (A1S2) set to NORM. Apply power to laser head as per Figure 4-1. (Use HP 6255A Dual DC Power Supply or its equivalent.) 8-27...

  • Page 88

    HP5501B Service Within 10 minutes of applying power to the laser head, the rear panel LED’s should reflect the following status. +15V SUPPLY UNBALANCE +15V POWER ON -15V SUPPLY UNBALANCE -15V POWER ON +15V FUSE READY OFF or FLASHING -15V FUSE LASER ON Disconnect power from laser head.

  • Page 89

    HP5501B Service +15V SUPPLY UNBALANCE LED should turn on at a maximum of +16.6 Volts. Adjust +15 Volt supply to +13 Volts. -15V SUPPLY UNBALANCE should turn on at a maximum of +13.4 Volts. Readjust ±15 Volt supplies to 15V ± 0.3 Volts. 8-87.

  • Page 90

    HP5501B Service 5. Turn the power off and disconnect the high voltage connector. Carefully connect a high voltage probe, (you will need to make a jumper to extend the probe into the high voltage connector). 6. Turn power back on and perform an open circuit voltage test. Before performing the open circuit voltage test, wait until the laser is in optical mode.

  • Page 91: Figure 8-18. High Voltage Power Supply, Schematic Diagram

    HP5501B Service Figure 8-18. High Voltage Power Supply, Schematic Diagram 8-31...

  • Page 92: Dividers Ⓑ

    HP5501B Service 8-91. A3 CONTROLLER/REFERENCE BOARD AND A4 SAMPLER BOARD CIRCUIT THEORY 8-92. Introduction 8-93. Figure 8-18 (two sheets) shows the schematic diagram for the A3 Controller/Reference Board and the A4 Sampler Board. 8-94. The A1, A3, and A4 boards contain the electronics for the following portions of the Laser Head Block Diagram: •...

  • Page 93: State Machine Ⓕ

    HP5501B Service Figure 8-19. State Machine Timing Diagram 8-99. State Machine Ⓕ 8-100. The state machine, consisting of U3, U4B, and U8A, determines the four states of controller operation. The warmup mode is divided into two states, preheat and heater qualified. The optical mode is divided into locking and locked states (see Figure 8-3, Flow Diagram for State Machine).

  • Page 94: Liquid Crystal Ⓓ

    HP5501B Service 8-104. When OPTICAL goes high, the state machine enters the locking state and optical feedback controls the heater. After this state has been held for 50 seconds, LTO [U1F (Pin 12)] goes high and the controller enters the locked state. If REF ON (a signal from the Reference Receiver) is low, the entire circuit will be reset by the Power-On-Reset circuit.

  • Page 95: A1/a3 Power Amplifier Ⓘ

    HP5501B Service 8-117. The first counter (A3U6) in the divider section controls the liquid crystal and the sample and hold circuits. A sample and hold is performed once per cycle of n.28 alternating between the vertical and horizontal components [see Figure 8-8 (Optical Mode Timing Diagram)]. Thus each component is sampled once every 2.56 seconds.

  • Page 96: Reference Receiver Ⓛ

    HP5501B Service 8-121. Reference Receiver Ⓛ NOTE A TILDE ("~") PRECEDING ALL SIGNALS INDICATES NEGATIVE-TRUE LOGIC. 8-122. The reference receiver consists of photodiode A3CR5, an amplifier A3U17, a transistor level shifter A3Q6, and associated passive components. The receiver amplifies and converts the sinusoidal output from A3CR5 to a square wave.

  • Page 97: A3 Controller/reference Board Troubleshooting

    HP5501B Service 8-133. A3 CONTROLLER/REFERENCE BOARD TROUBLESHOOTING 8-134. Service for A3 is divided into the following procedures, consult paragraph 8-64, HP5501B Trouble Isolation to determine which procedure to use. Digital Photodiode and Amplifier Liquid Crystal Subtracting Sample and Hold Power Amplifier Warmup Error Amplifier Power Supplies Reference Receiver...

  • Page 98: Digital Troubleshooting

    HP5501B Service 8-137. Digital Troubleshooting 8-138. This procedure covers the clock, dividers, power-on-reset, and state machine blocks of the A3 board. The procedure assumes that the power supplies are functioning properly. The procedure requires use of standard troubleshooting procedures which are outlined in paragraph 8-136. 8-139.

  • Page 99: Table 8-3. Ic A3u4 And A3u6 Divider Check

    HP5501B Service If these are OK, go to step n. If the signature analyzer will not take signatures, then there is a malfunction in the dividers or power on-reset sections go to step e. If the signature analyzer works, but one or more signatures are wrong, go to step f. Set HTR OK to HI, REF ON to HI, and RESET to TEST.

  • Page 100

    HP5501B Service With settings same as step I, check that U4 pins 1, 2, 9, 12, 13, and 16 are all high. If not, U4 is bad. At this point, the digital section should be OK. Set REF ON to HI, HTR OK to “X”, and ALL other jumpers to left. U9 (Pin 13) (HTRQ) should be high.

  • Page 101: Photodiode And Amplifier Troubleshooting

    HP5501B Service Table 8-4. Signature Table 41A5 4UHP CCPC 6678 4CCA 41A5 CCPC 4CCA F9C3 0000 7U30 41A5 0000 FP96 0000 41A5 4H86 8816 8816 41A5 FP96 8A5F P861 FO9F 27HH A5P7 41A5 F9C3 4A39 41A5 0000 4UHP CU8C 0000 4UHP 0000 UA4P...

  • Page 102: Liquid Crystal Troubleshooting

    Set A1S2 to TEST. Verify laser is on. Set all jumpers on A3 to left except LIQ CRYS to PASS. Insert test polarizer (HP Part Number 1000-0616) between laser assembly and sampler assembly. The bottom edge of the polarizer should be parallel to the base of the HP5501B.

  • Page 103

    Place LIQ CRYS jumper to NRM. TP16 will alternate between about 0 V to about -5 V. Record these voltages (the 11 V function of the HP 5005A/B is useful here). Measure voltage atTP13. It should be the same 0 V reading as at TP16, within 20 mV. If OK, go to step k.

  • Page 104: Power Amplifier Troubleshooting

    HP5501B Service 8-146. Power Amplifier Troubleshooting 8-147. The heart of the power amplifier is A3U20, a fixed-frequency pulse-width-modulator control unit. The IC operates at a fixed frequency set by A3R63 and C38. The outputs are used to control the amount of ±1SV current supplied to the laser assembly during the warmup and optical modes of operation.

  • Page 105: Figure 8-21. E-ref [u20 (pin 9)]

    HP5501B Service Is U13 (Pin 6) < -10 Vdc (i.e., more negative)? If yes, go to step I. If no, go to step f. Is U13 (Pin 3) approximately -0.1 Vdc? If yes, check R33 or U13. If no, check R49, R50, R51, and U13.

  • Page 106: Warm-up Error Amplifier Troubleshooting

    HP5501B Service 8-148. Warm-Up Error Amplifier Troubleshooting 8-149. This procedure assumes the power amplifier is functioning properly. Set HEATER jumper to OFF. A3TP11 waveform (see Figure 8-20) changes to 0 Vdc. If yes, go to step b. If no, go to power amplifier servicing. Is A3TP15 voltage +0.2 to +0.6 Vdc? If yes, go to step c.

  • Page 107: Reference Receiver Troubleshooting

    HP5501B Service 8-152. Reference Receiver Troubleshooting With power removed from the HP5501B, set the - REF ON jumper on A3 to LO and HTR OK to HI. Apply power to 55018. Does the READY LED eventually start blinking then remain on continuously? If no, see HP5501B Trouble Isolation Procedure, paragraph 8- 72 and procedures recommended therein.

  • Page 108: Table 8-6. A3u17 Reference Receiver Test Voltages

    HP5501B Service If no activity is found, check U17 (Pin 2). If Pin 2 is at a TTL high level or changing states, then either the laser is not tuned properly, the Reference Receiver is failing or not receiving adequate signal. Verify laser tuning according to step c before continuing with step d. If U17 Pin 2 is at a TTL low level and there is no output activity as described above, then U17 may be bad or its output may be shorted.

  • Page 109

    1. Remove power from the HP5501B. 2. Remove A4. 3. Rest the test polarizer, HP Part Number 1000-0616 (supplied with the HP5501B), against the exposed Reference Receiver exit port of the sampler. The test polarizer will serve as a viewing screen in order to examine the laser beam which is normally incident on the Reference Receiver photodiode.

  • Page 110: Figure 8-23. A1 Connector Board Component Locator

    HP5501B Service COMPONENT SIDE CIRCUIT SIDE SERIES 2632, REV A Figure 8-23. A1 Connector Board Component Locator 8-50...

  • Page 111: Figure 8-23. A1 Connector Board Component Schematic Diagram

    HP5501B Service Figure 8-23. A1 Connector Board Component Schematic Diagram 8-51...

  • Page 112: Figure 8-23. A1 ↔ A3 Connector Pin Table

    DESCRIPTION FROM BLOCK Warmup Through A3U3B(6) Ⓕ A1R10 to A1Q4 Through A3U7(3) A1R18 to A1CR3, Ⓒ and A1J5(C) Digital Ground 5501B Circuitry A1J5(D) Ⓒ —— — — — +15V Heater Control Drive A1Q8 A3U20(12) Ⓘ +15V 5501B Circuitry A1J5(A) Ⓒ...

  • Page 113

    HP5501B Service +15 VOLTS +15 VOLTS -≈ -≈ 0 VOLTS 0 VOLTS -15 VOLTS -15 VOLTS -≈ -≈ Waveform photographs ① ② A3TP11 or A1TP3. HEATER SENSE During Warmup A3TP11 or A1TP3. HEATER SENSE During Optical taken with all test Mode (Locking) Mode jumpers in the NRM (left-...

  • Page 114

    HP5501B Service +4 VOLTS -≈ +2 VOLTS -≈ - 0 VOLTS - 0 VOLTS ⑥ A3U20 (Pin 9). E-REF or Subtracting Sample and Hold Difference Input Waveform Oscilloscope Settings: Waveform photographs ⑤ Vertical Input: 1 Volts/Division A3U20 (Pin 7).RC Input Waveform to U20's Internal taken with all test Horizontal Input: 20 μsec/Division Oscillator/Logic Circuitry (~50 kHz)

  • Page 115: Figure 8-24. A3 Controller/reference Board (05501-60027) And A4 Sampler Board (05501-60029 Schematic Diagram (sheet 1 Of 2)


  • Page 116: Figure 8-24. A3 Controller/reference Board (05501-60027) And A4 Sampler Board (05501-60029 Schematic Diagram (sheet 2 Of 2)

    HP5501B Service Figure 8-24. A3 Controller/Reference Board (05501-60027) and A4 Sampler Board (05501-60029) Schematic Diagram (Sheet 2 of 2) 8-56...

  • Page 117

    HP5501B Service TABLE OF ACTIVE ELEMENTS REFERENCE HP PART NO. MFG PART NO. DESIGNATOR CR1,7-8 1901-0050 1N4150 1901-0731 1N4004G 1980-0770 OP913(SELECTED) 1901-0518 SAME 1990-0485 HLMP-1503 1990-0487 HLMP-1401 Q6-7 1854-0215 2N3904 1820-1416 SN74LS14N 1820-2889 SN74ALS11N U3,8 1820-2488 SN74ALS74AN 1820-2078 SN74LS490N 1820-2635...

  • Page 119: Service Notes

    Service 9 SERVICE NOTES 9-1. Service Note 5501-02A July 2001 SUPERSEDES: 5501 B-02 5501B Laser Heads Serial Numbers: OOOOAOOOOO / 9999A99999 USOOOOOOOO / US99999999 To Be Performed By: Agilent-Qualified Personnel Situation: In many incidences, the temperature adjustment process for the laser heads had been found being adjusted incorrectly.

  • Page 120

    HP5501B Service To make sure that the tube does not begin heating perform the following with the laser head "OFF": a. On A3, the control board, change the HEATER jumper, JMP7, from NRM to OFF. b. ON A1, connector board, UNPLUG J3, the Hi Voltage Power Supply. Turn "ON"...

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