Tektronix 2715 User manual

Service Manual
2715
Spectrum Analyzer
Volume 1
070-9096-06
This document supports firmware version
12.01.95 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 this product will be free from defects in materials and workmanship for a period of one (1) year
from the date of shipment. If any such 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; or c) 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 WITH RESPECT TO THIS PRODUCT IN LIEU OF ANY
OTHER WARRANTIES, EXPRESSED 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.

2715 Spectrum Analyzer Service Manual i
Table of Contents
General Safety Summary ix...................................
Service Safety Summary xi....................................
Preface xv...................................................
Specifications
Electrical Characteristics 1-1..........................................
Operating Information
Instrument Description 2-1............................................
Conformance to Industry Standards 2-2..................................
Product Service 2-2..................................................
Instrument Construction 2-3...........................................
Installation and Preparation for Use 2-3..................................
Power Cord 2-3.....................................................
Replacing the Fuse 2-4...............................................
Selected Components 2-4.............................................
Assembly and Circuit Numbering 2-4...................................
Accessories 2-4.....................................................
Menus 2-4.........................................................
SWP/TRG Menu Structure 2-6.........................................
UTIL Menu Structure
(1 of 2) 2-7.....................................................
UTIL Menu Structure
(2 of 2) 2-8.....................................................
MRK/FREQ Menu Structure 2-8.......................................
CATV/APPL CATV Measurements Page 1 Menu Structure (1 of 3) 2-9........
CATV/APPL CATV Measurements Page 1 Menu Structure (2 of 3) 2-10........
CATV/APPL CATV Measurements Page 1 Menu Structure (3 of 3) 2-11........
CATV/APPL CATV Measurements Page 2 Menu Structure (1 of 2) 2-12........
CATV/APPL CATV Measurements Page 2 Menu Structure (2 of 2) 2-13........
CATV/APPL Applications Menu Structure 2-14............................
DEMOD Menu Structure 2-14..........................................
DSPL Menu Structure 2-15............................................
USER DEF Menu Structure 2-15........................................
INPUT Menu Structure 2-16...........................................
Theory of Operation
Block Diagram Description 3-1........................................
Center Frequency Control 3-5.........................................
1st LO Buffer 3-7...................................................
Sweep 3-7.........................................................
Display System 3-8..................................................
Circuit Description 3-9........................................
Attenuator and 1st Converter 3-9.......................................
RF Mother Board and Phase Locked 2nd LO 3-12..........................

Table of Contents
ii 2715 Spectrum Analyzer Service Manual
1st LO Interface, 1st LO, and 1st LO Buffer Amplifier 3-14..................
Reference Oscillator 3-16..............................................
Phase Lock Assembly (Center Frequency Control System) 3-21...............
Variable Resolution Module 3-33........................................
RF Options 3-35.....................................................
Log Amplifier 3-38...................................................
Display Storage 3-40..................................................
Microprocessor 3-60..................................................
GPIB, RS-232, Real Time Clock, NVRAM, and Gated Measurement Functions 3-74
Video Demodulator 3-78...............................................
Sweep 3-80.........................................................
Front Panel 3-83.....................................................
Power Supply (Primary and Secondary) 3-87..............................
Power Supply (Display) 3-91...........................................
Performance Verification
Incoming Inspection Test 4-1..........................................
Verification of Tolerance Values 4-1....................................
History Information 4-1..............................................
Equipment Required 4-2..............................................
Power-Up Procedure 4-3..............................................
Front Panel Operation 4-4.............................................
Performance Check Procedure 4-4......................................
Adjustment Procedures
Static Discharge Precautions 5-1.......................................
Recommended Test Equipment 5-2.....................................
Preparation 5-4.....................................................
Adjustments Requiring Flatness Correction 5-4...........................
Instrument Bottom View 5-5..........................................
Adjustments 5-6....................................................
Maintenance
Static Sensitive Components 6-1.......................................
Preventive Maintenance 6-2...........................................
Troubleshooting 6-6.................................................
Cal Debug Flags 6-8.................................................
Corrective Maintenance 6-13...........................................
Assembly Replacement Requiring Flatness Correction 6-17...................
Removing and Replacing Assemblies and Subassemblies 6-17................
Maintenance Adjustments 6-33.........................................
Options
Replaceable Electrical Parts
Diagrams
Replaceable Mechanical Parts

Table of Contents
2715 Spectrum Analyzer Service Manual iii
List of Figures
Figure 1-1: Typical Accuracy Limits for Carrier-to-Noise
Measurement 1-7..........................................
Figure 1-2: Typical Accuracy Limits for CTB Measurement 1-7......
Figure 1-3: Typical Accuracy Limits for Nongated CSO
Measurement 1-8..........................................
Figure 1-4: Typical Accuracy Limits for Gated CSO
Measurement 1-8..........................................
Figure 1-5: Typical ACL Measurement Limits for 2 dB Accuracy 1-9..
Figure 1-6: Typical D/U Measurement Range Limits for
2 dB Accuracy 1-9.........................................
Figure 1-7: Typical Digital Signal CSO Measurement Range Limit
for 2 dB Accuracy 1-10......................................
Figure 1-8: Typical Digital Signal CTB Measurement Range
Limit for 2 dB Accuracy 1-10.................................
Figure 2-1: 2715 Front Panel Keys 2-5............................
Figure 3-1: Main Block Diagram 3-2.............................
Figure 3-2: Display System Diagram 3-8..........................
Figure 3-3: Attenuator and 1st Converter Diagram 3-10..............
Figure 3-4: Equivalent Circuit for the Bandpass (4 Cavity)
Filter 3-11.................................................
Figure 3-5: Block Diagram of RF Mother Board 3-12................
Figure 3-6: 1st LO Interface and 1st LO Diagram 3-14...............
Figure 3-7: 1st LO Buffer Amplifier Diagram 3-15..................
Figure 3-8: Reference Oscillator Diagram 3-17......................
Figure 3-9: Crystal Heater and 15 V Regulation Circuit 3-18..........
Figure 3-10: Oscillator AC Equivalent 3-19........................
Figure 3-11: Oscillator DC Equivalent 3-20........................
Figure 3-12: Phase Lock Center Frequency Control
Configuration for Wide Spans (Unlocked, Sweep Main Coil) 3-28..
Figure 3-13: Phase Lock Center Frequency Control Configuration
for Moderate Spans (Unlocked, Sweep FM Coil) 3-29.............
Figure 3-14: Phase Lock Center Frequency Control Configuration
for Narrow Spans (Locked, Sweep VCO) 3-30...................
Figure 3-15: Variable Resolution Module Diagram 3-34..............
Figure 3-16: RF Options Diagram 3-36............................

Table of Contents
iv 2715 Spectrum Analyzer Service Manual
Figure 3-17: Timing Diagram for a Typical Write to the Control
Register 3-50...............................................
Figure 3-18: Timing Diagram of a Typical Sweep for the Horizontal
Tracking A/D Converter 3-51.................................
Figure 3-19: Sequence of Events When Writing Data to the
Waveform Memory 3-54.....................................
Figure 3-20: How a Vertical Scan is Performed 3-56.................
Figure 3-21: The Display of a Single Vector of a Waveform 3-57.......
Figure 3-22: A Single Column of Character Dots 3-57................
Figure 3-23: Vertical Output Integrator 3-58.......................
Figure 3-24: Microprocessor Block Diagram 3-61...................
Figure 3-25: Microprocessor Counter System (CPU) 3-62.............
Figure 3-26: Front Panel Block Diagram 3-83......................
Figure 3-27: How the Debounce Circuit Reacts to Key Closure 3-85....
Figure 3-28: Power Supply Primary Block Diagram 3-88.............
Figure 3-29: Display Amplifiers Block Diagram 3-91................
Figure 4-1: 3rd Order IM Test Setup (25 MHz Separation) 4-17.......
Figure 4-2: Harmonic Distortion Test Equipment Setup 4-18..........
Figure 4-3: 1 dB Compression Point Test Setup 4-20.................
Figure 4-4: Accessory Connector (J103) 4-22.......................
Figure 4-5: Test Equipment Setup for Checking Return Loss 4-28.....
Figure 4-6: Test Signal on Video Line 17 4-32.......................
Figure 4-7: Video Gating Check Waveform (NTSC Illustrated) 4-34....
Figure 4-8: IF Gating Check Waveform (NTSC Illustrated) 4-35......
Figure 5-1: Instrument Bottom View 5-5..........................
Figure 5-2: Display Storage Board Adjustment Locations 5-13........
Figure 5-3: Properly Adjusted Checkerboard Pattern 5-14...........
Figure 5-4: Locked 2nd LO and 5 MHz Bandpass Filter
Adjustments 5-16...........................................
Figure 5-5: Phase Lock CFC Module Adjustment and Test Point
Locations 5-17.............................................
Figure 5-6: Log Board Adjustment and Test Point Locations 5-21.....
Figure 5-7: CAL Level Adjustment on Reference Oscillator Board 5-26.
Figure 5-8: RF Option Adjustment Locations 5-28..................
Figure 5-9: Variable Resolution Module Adjustment Locations 5-29....
Figure 5-10: Flatness adjustment test setup (all instruments
except Option 50) 5-34.......................................

Table of Contents
2715 Spectrum Analyzer Service Manual v
Figure 5-11: Presetting the Flatness Adjustments on the
Log Board 5-35............................................
Figure 5-12: Gain Step Reference Test Setup 5-36...................
Figure 5-13: Internal Ref Ampltd Test Setup 5-38...................
Figure 5-14: SW410 on the Reference Oscillator Board 5-39..........
Figure 5-15: Adjustment and Test Point Locations on the
Sweep Board 5-41..........................................
Figure 5-16: Typical FM Adjustment Waveform 5-42................
Figure 5-17: HPF Tuning Criteria (at TP110M) 5-45.................
Figure 5-18: Typical Video Waveform 5-48.........................
Figure 5-19: Horizontal Sync Output 5-49.........................
Figure 5-20: Vertical Sync Output Waveform 5-50..................
Figure 5-21: E/O Output Waveform 5-51..........................
Figure 5-22: Test Equipment Characterization Using a Dual
Channel Power Meter for split75 5-59..........................
Figure 5-23: Test Equipment Characterization Using a
Single Channel Power Meter to Characterize the Power Meter
Output for split75 5-59......................................
Figure 5-24: Test Equipment Characterization Using a
Single Channel Power Meter to Characterize the DUT
Output for split75 5-59......................................
Figure 5-25: Test Equipment Characterization Using a Dual
Channel Power Meter for split50 5-60..........................
Figure 5-26: Test Equipment Characterization Using a
Single Channel Power Meter to Characterize the Power Meter
Output for split50 5-60......................................
Figure 5-27: Test Equipment Characterization Using a
Single Channel Power Meter to Characterize the DUT
Output for split50 5-60......................................
Figure 5-28: Flatness Test Setup (75 W) 5-62.......................
Figure 5-29: Flatness Test Setup (50 W) 5-62.......................
Figure 6-1: Main Extender and Secondary Extender 6-4............
Figure 6-2: Signal Steering Square Pins 6-5.......................
Figure 6-3: Surface Mounted Components Lead Configuration 6-14...
Figure 6-4: Top View of Assemblies and RF Deck 6-18...............
Figure 6-5: Assemblies Seen from the Bottom of the Spectrum
Analyzer 6-19..............................................
Figure 6-6: Removing the Front Panel 6-22........................
Figure 6-7: Locations of J510 and J550 on the Phase Lock
Assembly 6-23.............................................

Table of Contents
vi 2715 Spectrum Analyzer Service Manual
Figure 6-8: Connector Locations on the RF Deck 6-24...............
Figure 6-9: RF Deck Screws and Nuts 6-25.........................
Figure 6-10: Fan and Fan Mounting Springs Detail 6-29.............
Figure 6-11: Power Supply Assembly Removal (Bottom View) 6-31....
Figure 6-12: Removing Power Supply Attaching Nuts 6-32...........
Figure 6-13: Location of R602 on the Phase Lock CFC Board 6-34.....
Figure 7-1: Option 15 Installation 7-3............................
Figure 10-1: Cabinet 10-7.......................................
Figure 10-2: Front Panel 10-11....................................
Figure 10-3: Power Supply 10-15..................................
Figure 10-4: Chassis #1 10-18.....................................
Figure 10-5: Chassis #2 10-22.....................................
Figure 10-6: Accessories 10-25....................................