Tektronix WFM90D User manual

Service Manual
WFM90D and WFM91D
Handheld Waveform, Vector,
Picture, and Audio Monitor
071-1143-00
This document applies to firmware version 2.13
and above.
Warning
The servicing instructions are for use by qualified
personnel only. To avoid personal injury, do not
perform any servicing unless you are qualified to
do so. Refer to all safety summaries prior to
performing service.
www.tektronix.com

Copyright ©Tektronix, Inc. All rights reserved.
Tektronix 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.
Tektronix, Inc., P.O. Box 500, Beaverton, OR 97077
TEKTRONIX and TEK are registered trademarks of Tektronix, Inc.

WARRANTY
Tektronix 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. If a product proves defective during this
warranty period, Tektronix, at its option, either will repair the defective product without charge for parts and labor,
or will provide a replacement in exchange for the defective product.
In order to obtain service under this warranty, Customer must notify Tektronix of the defect before the expiration
of the warranty period and make suitable arrangements for the performance of service. Customer shall be
responsible for packaging and shipping the defective product to the service center designated by Tektronix, with
shipping charges prepaid. Tektronix shall pay for the return of the product to Customer if the shipment is to a
location within the country in which the Tektronix service center is located. Customer shall be responsible for
paying all shipping charges, duties, taxes, and any other charges for products returned to any other locations.
This warranty shall not apply to any defect, failure or damage caused by improper use or improper or inadequate
maintenance and care. Tektronix shall not be obligated to furnish service under this warranty a) to repair damage
resulting from attempts by personnel other than Tektronix representatives to install, repair or service the product;
b) to repair damage resulting from improper use or connection to incompatible equipment; c) to repair any
damage or malfunction caused by the use of non-Tektronix supplies; or d) to service a product that has been
modified or integrated with other products when the effect of such modification or integration increases the time
or difficulty of servicing the product.
THIS WARRANTY IS GIVEN BY TEKTRONIX IN LIEU OF ANY OTHER WARRANTIES, EXPRESS
OR IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. TEKTRONIX’
RESPONSIBILITY TO REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND
EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY.
TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT, SPECIAL,
INCIDENTAL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR
THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.

WFM90D and WFM91D Service Manual i
Table of Contents
General Safety Summary vii...................................
Service Safety Summary ix....................................
Preface xi...................................................
About This Manual xi...............................................
Related Manuals xi.................................................
Contacting Tektronix xii.............................................
Specifications
Specifications 1--1.............................................
Product Description 1--1..............................................
Characteristics Tables 1--2.............................................
Electrical Specifications 1--2...........................................
Physical Characteristics 1--7...........................................
Environmental Characteristics 1--8......................................
Certifications and Compliances 1--9.....................................
Operating Information
Installation 2--1...............................................
Mechanical Installation 2--1...........................................
Electrical Installation 2--4.............................................
Functional Overview 2--7.......................................
Keypad Controls 2--7.................................................
Side-Panel Connectors and Switches 2--10.................................
Onscreen Readouts 2--12...............................................
Using the Menus 2--15...........................................
Operating Menus 2--17................................................
Configuration Menu 2--21..............................................
Line Select Menu 2--26................................................
Theory of Operation
Theory of Operation 3--1.......................................
Input Board 3--1.....................................................
SDI Interface Board 3--1..............................................
Top Board 3-- 2......................................................
Bottom Board 3--2...................................................
Backlight Power Supply Board 3--2.....................................
LCD Display and Backlight 3--2........................................
Performance Verification
Performance Verification 4--1...................................
Summary Verification 4--2.............................................
Equipment Required 4--3..............................................
Performance Verification: Analog Section 4--5.....................

Table of Contents
ii WFM90D and WFM91D Service Manual
Sync Separation 4--5.................................................
Sweep Timing and Integral Linearity 4--6................................
Vertical Gain and Vertical Magnifier Registration 4--7.......................
Variable Gain Range and Vertical Position Range 4--7.......................
Overscan 4--8.......................................................
Input and DC Restorer Frequency Response 4--9...........................
Vector Phase Stability 4--11.............................................
Chrominance Bandwidth 4--12..........................................
Audio Gain and Frequency Response 4--13................................
Performance Verification: Digital Section 4--15......................
Check Sync Separation 4--15............................................
Check Frequency Response 4--16........................................
Check Frequency Response at X5 Gain 4--17...............................
Adjustment Procedures
Adjustments 5--1..............................................
Summary Adjustment 5--1.............................................
Equipment Required 5--2..............................................
Adjustment Procedures 5--3............................................
Adjustment Procedures: Analog Section 5--5.......................
Raster VCO 5--5.....................................................
Sweep Timing and Horizontal Mag Registration 5--5........................
Vertical Gain and X5 Gain Registration 5--7...............................
Frequency Response 5--7..............................................
Vector Quadrature Phase 5--9..........................................
VectorGainandX5GainPhase 5--9.....................................
Audio Gain 5--10.....................................................
Adjustment Procedures: Digital Section 5--11.......................
Vertical Gain 5--11....................................................
Frequency Response 5--12..............................................
VectorGainandX5GainPhase 5--12.....................................
Cable Margin 5--13...................................................
Maintenance
Maintenance 6--1..............................................
Cleaning 6--1.......................................................
After Repair Adjustments 6--2..........................................
Repackaging Instructions 6--2..........................................
Remove and Replace 6--3.......................................
Tools Required 6--3..................................................
Procedures 6--4......................................................
Troubleshooting Procedures 6--31.................................
Equipment Required 6--31..............................................
Battery-Fault Analysis 6--32............................................
Low-Voltage Power Supply 6--34........................................
Fault Symptom Table 6--35.............................................
Troubleshooting Flowcharts 6--36........................................
Connector Diagram 6--51..............................................

Table of Contents
WFM90D and WFM91D Service Manual iii
Options
Options 7--1..................................................
Options 7--1........................................................
Accessories 7--2.....................................................
Replaceable Mechanical Parts
Replaceable Parts List 8--1......................................
Parts Ordering Information 8--1.........................................
Using the Replaceable Parts List 8--2....................................
Diagrams
Diagrams 9--1.................................................

Table of Contents
iv WFM90D and WFM91D Service Manual
List of Figures
Figure 2--1: Installing the viewing hood 2--2.......................
Figure 2--2: Installing the desk stand 2--2..........................
Figure 2--3: Packing the Option 33 travel case 2--3..................
Figure 2--4: Removing the NiMH battery pack 2--5.................
Figure 2--5: Inside of the battery compartment, showing
polarity markings 2--6......................................
Figure 2--6: WFM90D keypad 2--8...............................
Figure 2--7: WFM90D and WFM91D side panels 2--11...............
Figure 2--8: Onscreen readout messages 2--12.......................
Figure 2--9: Waveform and Vector menus 2--15......................
Figure 2--10: Audio, Picture, and Waveform-in-Picture menus 2--16....
Figure 2--11: Line Select menu 2--16...............................
Figure 2--12: Configuration menu 2--22............................
Figure 3--1: Simplified block diagram 3--3.........................
Figure 4--1: --3 dB marks on the vector graticule 4--12................
Figure 5--1: NTSC graticule showing the vector gain adjustment 5--10..
Figure 6--1: Removing the top cover 6--5..........................
Figure 6--2: Installing the LCD display cable 6--7...................
Figure 6--3: Installing the LCD display 6--9........................
Figure 6--4: Installing the keypad 6--12............................
Figure 6--5: Installing the Top board shield 6--13....................
Figure 6--6: Installing the Bottom board 6--15.......................
Figure 6--7: Installing the SDI Interface board 6--16..................
Figure 6--8: Installing the battery cover 6--19.......................
Figure 6--9: Removal and replacement of the turnlock stud 6--20.......
Figure 6--10: Removing the NiMH battery pack 6--22................
Figure 6--11: Installed polarity of alkaline batteries 6--23..............
Figure 6--12: Battery contact installation alignment 6--25.............
Figure 6--13: Battery power-wire and turnlock stud receptacle
installation 6--26............................................
Figure 6--14: Battery orientation marker position 6--28...............
Figure 6--15: Installing the EMI suppressor 6--29....................

Table of Contents
WFM90D and WFM91D Service Manual v
Figure 6--16: Testing the battery charging circuit 6--32................
Figure 6--17: Flowchart for no display 6--37........................
Figure 6--18: Flowchart for distorted waveform display 6--38..........
Figure 6--19: Flowchart for no vector display 6--39...................
Figure 6--20: Flowchart for problems processing serial digital
input signals 6--40...........................................
Figure 6--21: Flowchart for bad audio display 6--41..................
Figure 6--22: Flowchart for no picture display 6--42..................
Figure 6--23: Flowchart for bad graticules and menus 6--43...........
Figure 6--24: Flowchart for all white display 6--44...................
Figure 6--25: Flowchart for untriggered waveform display 6--45........
Figure 6--26: Flowchart for unlocked vector display 6--46.............
Figure 6--27: Flowchart for vector display jitter 6--47.................
Figure 6--28: Flowchart for distorted vectors 6--47...................
Figure 6--29: Flowchart for problems with the instrument
controls 6--48...............................................
Figure 6--30: Flowchart for bad menus in the picture display 6--49.....
Figure 6--31: Flowchart for dim or blotchy display 6--50..............
Figure 6--32: Flowchart for bad displays except Picture mode 6--50.....
Figure 6--33: Circuit board connector and pin locations 6--51..........
Figure 8--1: Exploded view 8--4..................................
Figure 9--1: Interconnect diagram 9--1............................

Table of Contents
vi WFM90D and WFM91D Service Manual
List of Tables
Table 1--1: Vertical deflection system 1--2.........................
Table 1--2: DC restoration 1--4...................................
Table 1--3: Audio mode 1--5.....................................
Table 1--4: Horizontal deflection system 1--5......................
Table 1--5: Vector mode 1--6....................................
Table 1--6: Synchronization 1--7.................................
Table 1--7: Power source 1--7...................................
Table 1--8: Physical characteristics 1--7..........................
Table 1--9: Environmental characteristics 1--8.....................
Table 1--10: Certifications and Compliances 1--9...................
Table 2--1: Video readout messages 2--13...........................
Table 2--2: Waveform menu choices, analog and digital 2--18..........
Table 2--3: Vector menu choices, analog and digital 2--18.............
Table 2--4: Audio menu choices 2--19..............................
Table 2--5: Picture menu choices, analog and digital 2--19............
Table 2--6: WIP menu choices, analog and digital 2--20...............
Table 2--7: Configure menu choices 2--23..........................
Table 2--8: Default instrument settings 2--25........................
Table 2--9: Line Select menu choices 2--26..........................
Table 4--1: Summary verification procedure 4--2...................
Table 4--2: Equipment required for performance verification 4--3.....
Table 5--1: Summary adjustment 5--1............................
Table 5--2: Equipment required for adjustments 5--2...............
Table 6--1: Tools required for module removal 6--3.................
Table 6--2: Remove and replace procedure list 6--4.................
Table 6--3: Equipment required for troubleshooting 6--31............
Table 6--4: Low-voltage power supplies 6--34.......................
Table 6--5: Fault symptom table 6--35.............................
Table 7--1: Options 7--1........................................
Table 7--2: Standard accessories 7--2.............................
Table 7--3: Optional accessories 7--2..............................