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Service Manual WFM 90 and WFM 91 Handheld W aveform, V ector , Pictur e, and Audio Monitor 070-8969-04 This document supports firmware version 1.00 and above. W arning The servicing instructions are for use by qualified personnel only . T o avoid personal injury , do not perform any servicing unless you are qualified to do so.
Copyright © T ektronix, Inc. All rights reserved. T ektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supercedes that in all previously published material. Specifications and price change privileges reserved.
W ARRANTY T ektronix warrants that the products that it manufactures and sells will be free from defects in materials and workmanship for a period of one (1) year from the date of shipment.
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Service Assurance If you have not already purchased Service Assurance for this product, you may do so at any time during the product’ s warranty period.
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WFM 90 and WFM 91 Service Manual i T able of Contents General Safety Summary vii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Service Safety Summary xi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
T able of Contents ii WFM 90 and WFM 91 Service Manual Fault Symptom T able 6–35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T roubleshooting Flowcharts 6–36 . . . . . . . . . . . . . . . . . . . . .
T able of Contents WFM 90 and WFM 91 Service Manual iii List of Figures Figure 2–1: Installing the viewing hood 2–2 . . . . . . . . . . . . . . . . . . . . . . . . Figure 2–2: Installing the desk stand 2–2 . . . . . . . . . . . . . . . . . . .
T able of Contents iv WFM 90 and WFM 91 Service Manual Figure 6–23: Flowchart for all white display 6–43 . . . . . . . . . . . . . . . . . . . . Figure 6–24: Flowchart for untrigger ed waveform display 6–44 . . . . . . . . Figure 6–25: Flowchart for unlocked vector display 6–45 .
T able of Contents WFM 90 and WFM 91 Service Manual v List of T ables T able 1–1: V ertical deflection system 1–6 . . . . . . . . . . . . . . . . . . . . . . . . . . T able 1–2: DC restoration 1–7 . . . . . . . . . . . . . . . . . . . . . . . .
T able of Contents vi WFM 90 and WFM 91 Service Manual.
WFM 90 & WFM 91 Service Manual vii General Safety Summary Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it. Only qualified personnel should perform service pr ocedur es. T o avoid potential hazards, use this product only as specified.
General Safety Summary viii WFM 90 & WFM 91 Service Manual For information on replacing and recharging batteries specific to this product, refer to the detailed instructions provided in this manual. Replace Batteries Properly . Before replacing batteries, turn the instrument of f and disconnect the AC adapter .
General Safety Summary WFM 90 & WFM 91 Service Manual ix T erms in this Manual. These terms may appear in this manual: W ARNING. W arning statements identify conditions or practices that could r esult in injury or loss of life.
General Safety Summary x WFM 90 & WFM 91 Service Manual.
WFM 90 & WFM 91 Service Manual xi Service Safety Summary Only qualified personnel should perform service procedures. Read this Service Safety Summary and the General Safety Summary before performing any service procedures.
Service Safety Summary xii WFM 90 & WFM 91 Service Manual.
WFM 90 and WFM 91 Service Manual xiii Preface This manual provides instructions for servicing the WFM 90 and WFM 91 Handheld W aveform, V ector , Picture, and Audio Monitors. This manual describes features and specifications that are common to all generator modules.
Preface xiv WFM 90 and WFM 91 Service Manual.
WFM 90 and WFM 91 Service Manual xv Introduction Service Strategy NOTE . Thr oughout this manual, any field-r eplaceable component, assembly , or part of this oscilloscope is r eferr ed to generically as a module.
Introduction xvi WFM 90 and WFM 91 Service Manual The following services may be purchased to tailor repair and/or calibration of your WFM90 or WFM91 Handheld W aveform, V ector , Picture, and Audio Monitor to fit your requirements: Option M2. When you order option M2, you receive a five year warranty and remedial service agreement.
Introduction WFM 90 and WFM 91 Service Manual xvii Module Repair and Return. This service returns to you within 10 days the same module that you shipped to T ektronix. The module shipped is repaired, tested, and returned to you from the Beaverton, Oregon service center .
Introduction xviii WFM 90 and WFM 91 Service Manual.
Specifications.
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WFM 90 and WFM 91 Service Manual 1–1 Specifications This section includes the following information: H Product description H Characteristics tables Refer to Performance Requir ements on page 1–5 for the conditions over which the characteristics listed in this section are valid.
Specifications 1–2 WFM 90 and WFM 91 Service Manual The key features of this instrument are described below: Rasterized Color LCD Display . This instrument uses a color, four -inch diagonal, backlit, thin-film transistor (TFT) LCD raster display module.
Specifications WFM 90 and WFM 91 Service Manual 1–3 The video output will drive a remote monitor or video switcher . The audio signal is output through a mini-headphone stereo jack that outputs the mono input signal to both stereo channels. The audio volume is fixed for each reference level.
Specifications 1–4 WFM 90 and WFM 91 Service Manual W aveform-in-Picture Display Mode. The W aveform-in-Picture (WIP) display mode provides a 1/4-screen-sized window over the Picture display for any one of the W aveform, V ector , or Audio displays.
Specifications WFM 90 and WFM 91 Service Manual 1–5 Characteristics T ables The characteristics tables use the following abbreviations: Performance Requirement. All performance requirements in the characteristics tables are identified with Req and can be assured by performing the procedures in the Performance V erification section.
Specifications 1–6 WFM 90 and WFM 91 Service Manual T able 1–1: V ertical deflection system Category Description Frequency Response REF: Specifications apply for full screen height video input signal with V ari- able Gain off. REQ: Flat Filter 1 V Full Scale: 50 kHz to 6 MHz within 2% of response at 50 kHz.
Specifications WFM 90 and WFM 91 Service Manual 1–7 T able 1–1: V ertical deflection system (Cont.) Category Description DC Input Impedance (Unterminated) REQ: 15 k W . REF: With input switch in the HIZ position. Video Input Return Loss REF: 40 dB from 50 kHz to 6 MHz with 75 W termination on.
Specifications 1–8 WFM 90 and WFM 91 Service Manual T able 1–4: Horizontal deflection system Category Description Sweep REQ: Sweep will occur in all horizontal mode settings with or without synchroniza- tion. REF: Sweep Length: T wo Line and Two Field sweep length is nominally 12 divisions.
Specifications WFM 90 and WFM 91 Service Manual 1–9 T able 1–5: V ector mode (Cont.) Category Description Display Differential Phase REF: 1 ° . REF: Measured with 140 IRE (1 V) linearity signal (5 step, 10 step, or Ramp) with 40 IRE (300 mV) of subcarrier .
Specifications 1–10 WFM 90 and WFM 91 Service Manual T able 1–6: Synchronization Category Description Input Requirements REQ: Internal Reference: Composite video or black burst with sync amplitudes 40 IRE (300 mV P AL) 6 dB. REQ: External Reference: Sync amplitude between 143 mV and 4 V will synchro- nize sweeps.
Specifications WFM 90 and WFM 91 Service Manual 1–1 1 T able 1–8: Environmental characteristics (Cont.) Category Description Vibration — Operating REF: 15 minutes each axis at 0.015 inch, frequency varied from 10 Hz to 55 Hz to 10 Hz in 1-minute cycles with instrument secured to vibration platform.
Specifications 1–12 WFM 90 and WFM 91 Service Manual T able 1–10: Safety/EMI Category Description Certifications REQ: Designed to meet or exceed: ANSI/ISA S82 – Safety Standard for Electrical and Electronic T est, Measur- ing, Controlling, and Related Equipment.
Operating Information.
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WFM 90 and WFM 91 Service Manual 2–1 Operating Information This section contains the following information: H Mechanical and electrical installation instructions H Operating instructions that relate.
Operating Information 2–2 WFM 90 and WFM 91 Service Manual Figure 2–1: Installing the viewing hood Desk Stand. The optional desk stand provides the user with a stable means to hold the instrument upright on a flat surface. The prongs of the stand are inserted into the holes in the back of the instrument as illustrated in Figure 2–2.
Operating Information WFM 90 and WFM 91 Service Manual 2–3 Follow these instructions when physically installing this instrument: Power Source. This instrument is designed to operate from either six C-cell batteries, alkaline or rechargeable NiCad, or from an AC adapter wall unit producing 12 VDC.
Operating Information 2–4 WFM 90 and WFM 91 Service Manual Operating Information This section will acquaint you with the basic principles of operating this instrument so that you can service it. Detailed operating instructions are located in the user manual.
Operating Information WFM 90 and WFM 91 Service Manual 2–5 Power Switch. Press the ON button to toggle the instrument power on and off. The current instrument keypad and menu selections are saved when the instrument is turned off using this button. NOTE .
Operating Information 2–6 WFM 90 and WFM 91 Service Manual Arrow Buttons. The function of the Arrow Buttons is dependent on the current state of the instrument.
Operating Information WFM 90 and WFM 91 Service Manual 2–7 DC IN 11-18V Figure 2–4: Instrument side panels DC Input Power Connector . The DC IN power connector is a 2 mm plug which accepts a 12 VDC power input, ranging from +1 1 V to +18 V , using a negative center lead.
Operating Information 2–8 WFM 90 and WFM 91 Service Manual The following special operating modes can be activated through the menus: Amplitude Alarm Mode. The Amplitude Alarm mode provides a means to automatically monitor the signal amplitude for the W aveform and Audio displays.
Operating Information WFM 90 and WFM 91 Service Manual 2–9 Calibration Mode. The Calibration mode allows you to adjust the instrument to factory specifications, if necessary . The Calibration mode is entered by pressing and holding the CONFIG button for a few seconds.
Operating Information 2–10 WFM 90 and WFM 91 Service Manual H The instrument software version number is displayed when the Configura- tion menu is open with the DISPLA Y category selected. H The LOW BA T message is displayed when the instrument is battery operated and the remaining battery power has reached a critically low level.
Theory of Operation.
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WFM 90 and WFM 91 Service Manual 3–1 Theory of Operation This section contains a module-level description of the instrument circuitry . Block Diagram Description The following description is based on the block diagram in Figure 3–1. The signal input and output connectors are located on the Input board.
Theory of Operation 3–2 WFM 90 and WFM 91 Service Manual The Backlight Power Supply board uses the switched DC input voltage from the batteries or external DC input to generate the voltage for the display backlight. The backlight mounts into the display module.
Theory of Operation WFM 90 and WFM 91 Service Manual 3–3 16 Input Board Ref Va r Gain Ext Ref Audio In Video In Video Out Front Panel Keys Part of m P Rasterizer and Graphics V ert Defl Horiz Defl I.
Theory of Operation 3–4 WFM 90 and WFM 91 Service Manual.
Performance V erification.
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WFM 90 and WFM 91 Service Manual 4–1 Performance V erification This section contains the following information: H Summary verification procedure H List of equipment required to perform the procedure.
Performance V erification 4–2 WFM 90 and WFM 91 Service Manual T able 4–1: Summary verification procedure (Cont.) Procedure Page # Procedure Requirement V ector phase stability Phase Shift with Subcarrier Frequency Change from F SC to F SC 50 Hz (F SC 10 Hz P AL): 2 ° .
Performance V erification WFM 90 and WFM 91 Service Manual 4–3 T able 4–2: Equipment required for performance verification (Cont.) Equipment Description Equipment Example Minimum Requirements Frequency counter Range: 10 Hz to 10 MHz; Accuracy: 0.
Performance V erification 4–4 WFM 90 and WFM 91 Service Manual Performance V erification Procedures Perform the performance verification procedures to ensure that the instrument is operating properly and is meeting the performance requirements listed in the characteristic tables of the Specifications section.
Performance V erification WFM 90 and WFM 91 Service Manual 4–5 Perform the following steps before beginning the verification procedures: 1. Plug the AC power adapter into the instrument and then plug the adapter into the AC power source.
Performance V erification 4–6 WFM 90 and WFM 91 Service Manual This procedure verifies the following requirement: Sweep T iming Accuracy: 5 m s/Div . (1 Line), 10 m s/Div . (2 Line), and 1.0 m s/Div . (2 Line + MAG), 2%. 0.2 m s/Div . (1 Line + MAG) 3%.
Performance V erification WFM 90 and WFM 91 Service Manual 4–7 This procedure verifies the following requirement: 1 V olt Full Scale: 1 V input displayed within 1% of 140 IRE (1.
Performance V erification 4–8 WFM 90 and WFM 91 Service Manual 4. Set the V AC for a 799.9 mV output. 5. Check by adjusting the V ariable Gain controls that the signal amplitude can be displayed greater than 140 IRE (1000 mV P AL). 6. Select X5 GAIN from the Operating menu.
Performance V erification WFM 90 and WFM 91 Service Manual 4–9 This procedure verifies the following requirement: X1 Gain Response (Flat filter selected): 50 kHz to 6 MHz within 2% of response at 50 kHz. X5 Gain Response (Flat filter selected): 50 kHz to 6 MHz within 5% of response at 50 kHz.
Performance V erification 4–10 WFM 90 and WFM 91 Service Manual 17. Adjust the peak-to-peak detector Plus amplifier and input control fully counterclockwise. 18. Adjust the sine wave generator for a display amplitude of 100 IRE (700 mV P AL). 19. Note the digital multimeter readout level or the oscilloscope dc level.
Performance V erification WFM 90 and WFM 91 Service Manual 4–1 1 This procedure verifies the following requirement: Phase Shift with Subcarrier Frequency Change from F SC to F SC 50 Hz (F SC 10 Hz P AL): 2 ° . Phase Shift with Burst Amplitude Change from Nominal to 6 dB: 2 ° .
Performance V erification 4–12 WFM 90 and WFM 91 Service Manual 3. Set the leveled sine wave generator frequency to 3.58 MHz (4.43 MHz P AL) and adjust the amplitude control so that the circle overlays the graticule compass rose.
Performance V erification WFM 90 and WFM 91 Service Manual 4–13 11 . Check that the frequency readout on the leveled sine wave generator is between 3.98 and 4.18 MHz (4.83 and 5.03 MHz P AL). 12. Remove all signals from the WFM 90 or WFM 91 Handheld W aveform, V ector , Picture, and Audio Monitor .
Performance V erification 4–14 WFM 90 and WFM 91 Service Manual 15. Set the audio generator for a 50 Hz tone output, with an amplitude of +8.0 dBu. 16. Select 8 dBu from the Operating menu. 17. Check that the display amplitude is within 0.5 dB of the reference level graticule lines.
Adjustment Procedures.
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WFM 90 and WFM 91 Service Manual 5–1 Adjustment Procedures This section contains the following information: H Summary adjustment procedure H List of equipment required to perform the procedures H Ad.
Adjustment Procedures 5–2 WFM 90 and WFM 91 Service Manual Equipment Required T able 5–2 lists the required equipment and accessory items to perform the adjustment procedures. Minimum equipment specifications are followed by an example of equipment that meet these specifications.
Adjustment Procedures WFM 90 and WFM 91 Service Manual 5–3 Adjustment Procedures The WFM 90 or WFM 91 Handheld W aveform, V ector , Picture, and Audio Monitor does not have any internal adjustments. Instrument adjustments are made entirely from the front panel by assigning adjustment functions to the Arrow Buttons through the Calibration menu.
Adjustment Procedures 5–4 WFM 90 and WFM 91 Service Manual The following information provides you with an overview of how adjustments are made on the WFM 90 or WFM 91 Handheld W aveform, V ector, Picture, and Audio Monitor . Calibration Menu. T o enter the Calibration menu, press and hold the CONFIG button for a few seconds.
Adjustment Procedures WFM 90 and WFM 91 Service Manual 5–5 Perform the following steps to adjust the sweep timing and horizontal mag registration: 1.
Adjustment Procedures 5–6 WFM 90 and WFM 91 Service Manual 22. Adjust the Arrow Buttons for a sweep length of 12 major divisions. 23. Select CAL MENU , and then select SA VE . 24. Select 2H SWEEP from the Operating menu. 25. Select MAG REG from the Calibration menu, and then select CAL .
Adjustment Procedures WFM 90 and WFM 91 Service Manual 5–7 14. Select X5 GAIN from the Calibration menu, and then select X5 POS . 15. Adjust the Arrow Buttons to reposition the signal baseline back to the graticule baseline. 16. Select X1 GAIN from the Calibration menu.
Adjustment Procedures 5–8 WFM 90 and WFM 91 Service Manual 16. Set the leveled sine wave generator frequency to 50 kHz, and adjust the generator amplitude for exactly 100 IRE (700 mV P AL) of display . 17. Adjust the peak-to-peak detector Plus amplifier and input control fully counterclockwise.
Adjustment Procedures WFM 90 and WFM 91 Service Manual 5–9 Perform the following steps to adjust the vector gain and X5 gain phase: a. WFM 90 ONL Y — V erify that the television signal generator has setup turned on. b. Select VEC GAIN from the Calibration menu, select CAL , and then select TEST ON .
Adjustment Procedures 5–10 WFM 90 and WFM 91 Service Manual Perform the following steps to adjust the audio gain: 1. Connect the output from the audio generator to the AUDIO IN connector . 2. Set the audio generator for a 1 kHz tone output with an amplitude of +8.
Maintenance.
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WFM 90 and WFM 91 Service Manual 6–1 Maintenance This section contains instructions for servicing the WFM 90 or WFM 91 Handheld W aveform, V ector , Picture, and Audio Monitor that include the follo.
Maintenance 6–2 WFM 90 and WFM 91 Service Manual This instrument contains electrical components that are susceptible to damage from electrostatic discharge. Static voltages of 1 kV to 30 kV are common in unprotected environments. CAUTION. Static dischar ge can damage any semiconductor component in this instrument.
Maintenance WFM 90 and WFM 91 Service Manual 6–3 Inspection and Cleaning Preventive maintenance consists of cleaning, visual inspection, performance checking, and, if needed, readjustment. The preventive maintenance schedule established for the instrument should be based on the environment in which it is operated and the amount of use.
Maintenance 6–4 WFM 90 and WFM 91 Service Manual After cleaning, carefully check the instrument for defective connections, damaged parts, and improperly seated transistors or integrated circuits.
WFM 90 and WFM 91 Service Manual 6–5 Removal and Replacement This section contains the instructions on how you can remove and replace the customer replaceable modules and parts of the WFM 90 or WFM 91 Handheld W aveform, V ector , Picture, and Audio Monitor .
Removal and Replacement 6–6 WFM 90 and WFM 91 Service Manual Procedures T able 6–2 lists the removal and replacement procedures in this section and their starting page numbers.
Removal and Replacement WFM 90 and WFM 91 Service Manual 6–7 The top cover assembly contains replaceable subparts. Procedures for removing the subparts are included below . T op Cover . T o remove the top cover assembly , perform the following procedure: 1.
Removal and Replacement 6–8 WFM 90 and WFM 91 Service Manual 2. Gently lift the top cover off of the bottom cover . NOTE . When you ar e disassembling the WFM 90 or WFM 91, do not let dust accumulate inside of the top cover .
Removal and Replacement WFM 90 and WFM 91 Service Manual 6–9 LCD Display . T o remove the LCD display assembly , perform the following procedure: 1. Remove the top cover . Refer to T op Cover on page 6–7. 2. Disconnect the wires from the two backlight connectors.
Removal and Replacement 6–10 WFM 90 and WFM 91 Service Manual NOTE . Some early instruments used cushion pads instead of locating feet to hold the display module in position. If your instrument has cushion pads, r eplace the pads at this time with locating feet.
Removal and Replacement WFM 90 and WFM 91 Service Manual 6–1 1 Level the pad flush with display case. LCD locator feet (4) Long pad Short pad Standoff post inserts into LCD display case. Figure 6–3: Installing the LCD display LCD Display Padding. T o remove the LCD display padding, perform the following procedure: 1.
Removal and Replacement 6–12 WFM 90 and WFM 91 Service Manual 3. Remove the display padding from the side of the LCD display module. 4. Clean any remaining glue residue from the side of the LCD display module. Refer to Cleaning on page 6–3. T o replace the LCD display padding, perform the following procedure: 1.
Removal and Replacement WFM 90 and WFM 91 Service Manual 6–13 The T op board assembly contains replaceable subparts. Procedures for removing the subparts are included below . T op Board. T o remove the T op board, perform the following procedure: 1.
Removal and Replacement 6–14 WFM 90 and WFM 91 Service Manual Pull nub through board with tweezers Keypad T op board Figure 6–4: Installing the keypad 3. Install the T op board. Refer to T op Boar d on page 6–13. 4. Install the top cover . Refer to T op Cover on page 6–7.
Removal and Replacement WFM 90 and WFM 91 Service Manual 6–15 Lift up the board to slip the shield underneath the top board. Shield Fold tab The shield tab goes on top of the board post and under the circuit board. Figure 6–5: Installing the T op board shield 2.
Removal and Replacement 6–16 WFM 90 and WFM 91 Service Manual T o remove the Bottom board, perform the following procedure: 1. Remove the top cover . Refer to T op Cover on page 6–7. 2. Remove the LCD display module. Refer to LCD Display on page 6–9.
Removal and Replacement WFM 90 and WFM 91 Service Manual 6–17 Align the Backlight and Input boards into the slots of the bottom cover Backlight board Input board assembly Figure 6–6: Installing the Bottom board T o remove the Backlight board, perform the following procedure: 1.
Removal and Replacement 6–18 WFM 90 and WFM 91 Service Manual 4. Install the T op board. Refer to T op Boar d on page 6–13. 5. Install the LCD display module. Refer to LCD Display on page 6–9. 6. Install the top cover . Refer to T op Cover on page 6–7.
Removal and Replacement WFM 90 and WFM 91 Service Manual 6–19 T o replace the battery cover assembly , perform the following procedure: 1. Place the lower lip of the battery cover into the instrument housing and press the top portion of the cover into the instrument.
Removal and Replacement 6–20 WFM 90 and WFM 91 Service Manual T o replace the carrying strap, perform the following procedure: 1. Insert the two standoff studs of the carrying strap through the battery cover and install the two retaining nuts. 2. Install the battery cover .
Removal and Replacement WFM 90 and WFM 91 Service Manual 6–21 T o replace the turnlock stud and bushing, perform the following procedure: 1. Press the turnlock stud into the bushing. 2. T o install the turnlock stud and bushing into the battery cover , press firmly on the turnlock stud head.
Removal and Replacement 6–22 WFM 90 and WFM 91 Service Manual Press Grasp wire Figure 6–9: Removing the NiCad battery pack T o replace the NiCad battery pack, perform the following procedure: 1. Press the battery connector onto the jumper in the battery compartment.
Removal and Replacement WFM 90 and WFM 91 Service Manual 6–23 T o replace the C-size alkaline batteries, perform the following procedure: 1. Press the batteries into place according to the polarity label on the bottom of the battery compartment. See Figure 6–10.
Removal and Replacement 6–24 WFM 90 and WFM 91 Service Manual 4. Lift the Bottom board slightly out of the top cover so that you can pull the battery-power wires from jumper J21 of the Bottom board. See Figure 6–12. T o replace the bottom cover , perform the following procedure: 1.
Removal and Replacement WFM 90 and WFM 91 Service Manual 6–25 Alignment ridge Retaining lip Battery contacts Figure 6–1 1: Battery contact installation alignment 4. Push the battery contact through the slot on the bottom cover . T o replace the battery contacts, perform the following procedure: 1.
Removal and Replacement 6–26 WFM 90 and WFM 91 Service Manual Depress receptacle prongs T urnlock stud receptacle Black wire Red wire Solder only this side Receptacle prongs Figure 6–12: Battery power-wire and turnlock stud receptacle installation 4.
Removal and Replacement WFM 90 and WFM 91 Service Manual 6–27 T o replace the turnlock stud receptacle, perform the following procedure: 1. Push the turnlock stud receptacle through the bottom cover . Be sure the retaining fingers snap into position.
Removal and Replacement 6–28 WFM 90 and WFM 91 Service Manual T o replace the battery orientation marker and/or the battery cushion pad, perform the following procedure: 1. T o replace the battery cushion pad and the battery orientation marker , peel off the protective covering of the adhesive surface of the battery cushion pad.
Removal and Replacement WFM 90 and WFM 91 Service Manual 6–29 4. Peel off the protective covering of the adhesive surface of the battery orientation marker . 5. Position the battery orientation marker in place above the battery cushion pad before you press it onto the battery cushion pad.
Removal and Replacement 6–30 WFM 90 and WFM 91 Service Manual.
WFM 90 and WFM 91 Service Manual 6–31 T roubleshooting Procedures This section contains the following information starting on the listed pages: H List of equipment required to perform the procedures.
T roubleshooting Procedures 6–32 WFM 90 and WFM 91 Service Manual Battery-Fault Analysis Use this procedure to troubleshoot battery or battery charging problems when the instrument functions properly when powered by the AC adapter .
T roubleshooting Procedures WFM 90 and WFM 91 Service Manual 6–33 NOTE . If the jumper wir es will not stay secur ely attached to the battery connector pins, you will need to r emove the instrument bottom case to obtain access to the battery connector pins on the Bottom boar d.
T roubleshooting Procedures 6–34 WFM 90 and WFM 91 Service Manual NOTE . If the jumper wir es will not stay secur ely attached to the battery connector pins, you will need to r emove the instrument bottom case to obtain access to the battery connector pins on the Bottom boar d.
T roubleshooting Procedures WFM 90 and WFM 91 Service Manual 6–35 T able 6–4: Low-voltage power supplies Supply T est Point Output Ripple +8 V J9, pin 13 40 mV 30 mV –8 V J9, pin 14 40 mV 30 mV +5 V J9, pin 15 25 mV 60 mV 6. If the low-voltage power supplies are operating properly , proceed to Fault Symptom T able .
T roubleshooting Procedures 6–36 WFM 90 and WFM 91 Service Manual 6. Connect a 75% color bar test signal to the VIDEO IN connector and connect the VIDEO OUT connector to the picture monitor . 7. Locate your fault symptom in T able 6–5 and go to the flowchart indicated to isolate the faulty module.
T roubleshooting Procedures WFM 90 and WFM 91 Service Manual 6–37 Is the Backlight broken? (The Display module will have a rattle inside.) Press the front panel ON button and then the PIX mode button. Is the Backlight on? (Look in the end of the Display module where the high voltage is attached.
T roubleshooting Procedures 6–38 WFM 90 and WFM 91 Service Manual Use this procedure when the graticule is ok, but the Waveform display is distorted or not visible. Remove the Display module and Backlight board. Power up the instrument and select DEF AUL T PRESET s from the CONFIGURE menu.
T roubleshooting Procedures WFM 90 and WFM 91 Service Manual 6–39 Use this procedure when the graticule is ok, but there is no V ector display . Remove the Display module and Backlight board. Power up the instrument and select DEF AUL T PRESET s from the CONFIGURE menu.
T roubleshooting Procedures 6–40 WFM 90 and WFM 91 Service Manual Use this procedure when the graticule is ok, but the Audio display is distorted or not visible. Remove the Display module and the Backlight board. Power up the instrument and select DEF AUL T PRESET s from the CONFIGURE menu.
T roubleshooting Procedures WFM 90 and WFM 91 Service Manual 6–41 Replace the T op board. Replace the Bottom board. Are the Display drive signals ok? Check the Display drive signals: (Probe J16 from the back of the Bottom board.) J16-6 = (B) 2 VDC, 2.
T roubleshooting Procedures 6–42 WFM 90 and WFM 91 Service Manual Use this procedure when the graticule and menu are bad, but the PIX mode is ok (moderate to severe vertical flutter). No Ye s Perform the Raster VCO adjustment, if possible, in the Adjustment procedures.
T roubleshooting Procedures WFM 90 and WFM 91 Service Manual 6–43 Replace the Bottom board. Are all of these signals correct? Replace the Display module. Use this procedure when the display is all white. Remove the Display module and Backlight board.
T roubleshooting Procedures 6–44 WFM 90 and WFM 91 Service Manual Are the sync pulses ok? Replace the T op board. Check for vertical and horizontal sync pulses: (J9 is on T op Board.) J9-18 = TTL level V -rate sync locked to the input signal. J9-19 = TTL level H-rate sync locked to the input signal.
T roubleshooting Procedures WFM 90 and WFM 91 Service Manual 6–45 Use this procedure when the V ector display is unlocked. Remove the Display module and Backlight board. Connect the AC Adapter and power up the instrument. Select INT REF using the CONFIGURE menu.
T roubleshooting Procedures 6–46 WFM 90 and WFM 91 Service Manual Use this procedure when there is V ector display jitter . This problem can be caused by either the T op or Bottom boards, and can only be determined by replacing these boards one at a time.
T roubleshooting Procedures WFM 90 and WFM 91 Service Manual 6–47 Use this procedure when there is an instrument control problem. Ye s Replace the T op Board first. These problems can be caused by either the T op or Bottom boards, and can only be determined by replacing these boards one at a time.
T roubleshooting Procedures 6–48 WFM 90 and WFM 91 Service Manual Use this procedure when the menus are horizontally unlocked (tearing) in the Picture display mode. Ye s No Check the horizontal and vertical sync signals on the Bottom board: (J9 is on T op board.
T roubleshooting Procedures WFM 90 and WFM 91 Service Manual 6–49 Use this procedure when the display is dim or blotchy . Replace the Backlight in the Display module. Figure 6–30: Flowchart for dim or blotchy display Use this procedure when all of the display modes are bad except Picture when no menus are displayed.
T roubleshooting Procedures 6–50 WFM 90 and WFM 91 Service Manual Connector Diagram Figure 6–32 illustrates the connector and pin locations of the circuit board connectors listed in the troubleshooting flowcharts.
Options.
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WFM 90 and WFM 91 Service Manual 7–1 Options and Accessories This section lists the instrument options and accessories that can be ordered for the WFM 90 or WFM 91 Handheld W aveform, V ector, Picture, and Audio Monitor . Refer to Parts Or dering Information on page 8–1 for information on how to order parts for this instrument.
Options and Accessories 7–2 WFM 90 and WFM 91 Service Manual Accessories The standard accessories are shipped with every instrument while the optional accessories must be ordered separately . The part numbers to use when you order any of the following accessories are listed in Mechanical Parts List on page 8–7.
Replaceable Parts.
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WFM 90 and WFM 91 Service Manual 8–1 Replaceable Parts List This section contains a list of the replaceable modules for this instrument. Use this list to identify and order replacement parts. Parts Ordering Information Replacement parts are available through your local T ektronix, Inc.
Replaceable Parts List 8–2 WFM 90 and WFM 91 Service Manual Using the Replaceable Parts List T able 8–1 describes each column in the replaceable parts list. T able 8–1: Replaceable parts list column descriptions Column Name Description Fig. & Index Number Items in this column are referenced to the exploded view item numbers.
Replaceable Parts List WFM 90 and WFM 91 Service Manual 8–3 Manufacturers Cross Index Mfr . Code Manufacturer Address City , State, Zip Code 0DWW6 MICRO POWER ELECTRONICS 7973 SW CIRRUS DRIVE BLDG 2.
Replaceable Parts List 8–4 WFM 90 and WFM 91 Service Manual A2 A3 A4 A5 A1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 .
Replaceable Parts List WFM 90 and WFM 91 Service Manual 8–5 Replaceable Parts List Fig. & Index Number T ektronix Part Number Serial No. Effective Serial No.
Replaceable Parts List 8–6 WFM 90 and WFM 91 Service Manual Replaceable Parts List (Cont.) Fig. & Index Number Mfr . Part Number Mfr . Code Name & Description Qty Serial No.
Replaceable Parts List WFM 90 and WFM 91 Service Manual 8–7 Replaceable Parts List (Cont.) Fig. & Index Number Mfr . Part Number Mfr . Code Name & Description Qty Serial No.
Replaceable Parts List 8–8 WFM 90 and WFM 91 Service Manual Replaceable Parts List (Cont.) Fig. & Index Number Mfr . Part Number Mfr . Code Name & Description Qty Serial No.
Diagrams.
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WFM 90 and WFM 91 Service Manual 9–1 Diagrams This section contains the interconnect diagram for the WFM 90 and WFM 91 Handheld W aveform, V ector , Picture, and Audio Monitor .
Diagrams 9–2 WFM 90 and WFM 91 Service Manual.
Ein wichtiger Punkt beim Kauf des Geräts Tektronix WFM91 (oder sogar vor seinem Kauf) ist das durchlesen seiner Bedienungsanleitung. Dies sollten wir wegen ein paar einfacher Gründe machen:
Wenn Sie Tektronix WFM91 noch nicht gekauft haben, ist jetzt ein guter Moment, um sich mit den grundliegenden Daten des Produkts bekannt zu machen. Schauen Sie zuerst die ersten Seiten der Anleitung durch, die Sie oben finden. Dort finden Sie die wichtigsten technischen Daten für Tektronix WFM91 - auf diese Weise prüfen Sie, ob das Gerät Ihren Wünschen entspricht. Wenn Sie tiefer in die Benutzeranleitung von Tektronix WFM91 reinschauen, lernen Sie alle zugänglichen Produktfunktionen kennen, sowie erhalten Informationen über die Nutzung. Die Informationen, die Sie über Tektronix WFM91 erhalten, werden Ihnen bestimmt bei der Kaufentscheidung helfen.
Wenn Sie aber schon Tektronix WFM91 besitzen, und noch keine Gelegenheit dazu hatten, die Bedienungsanleitung zu lesen, sollten Sie es aufgrund der oben beschriebenen Gründe machen. Sie erfahren dann, ob Sie die zugänglichen Funktionen richtig genutzt haben, aber auch, ob Sie keine Fehler begangen haben, die den Nutzungszeitraum von Tektronix WFM91 verkürzen könnten.
Jedoch ist die eine der wichtigsten Rollen, die eine Bedienungsanleitung für den Nutzer spielt, die Hilfe bei der Lösung von Problemen mit Tektronix WFM91. Sie finden dort fast immer Troubleshooting, also die am häufigsten auftauchenden Störungen und Mängel bei Tektronix WFM91 gemeinsam mit Hinweisen bezüglich der Arten ihrer Lösung. Sogar wenn es Ihnen nicht gelingen sollte das Problem alleine zu bewältigen, die Anleitung zeigt Ihnen die weitere Vorgehensweise – den Kontakt zur Kundenberatung oder dem naheliegenden Service.
