Here are some links to repair tips and reference material.
vintageTEK Museum Product Repair
310 Calibration Procedure January 1956
460 Series / 475 Repair Tips (video)
468 Mostek MKB36000 ROM Repairs
535 Calibration Procedure December 1955
576 High Voltage Transformer Repair
The 4051 had three firmware releases during its production. This July 7, 1976 document details the corrections and the serial number breaks for the various releases.
4051 Firmware Releases
7854 Mostek MKB36000 ROM Repairs
Circuit Descriptions with Chuck Miller
Dallas DS1287 Dead Battery Repair
We don't know the source or reason for this document which describes the more popular transistors used at Tektronix.
Everything About Transistors
Fundamental Electronic Concepts for Oscilloscope Use and Maintenance 1956
Keytronic Capactive Keyboard Repair
Military Nomenclature / Modified Products
This undated document describes the phase-in of earthtone colors instead of the traditional Tek blue.
New Color Scheme
Primer of Waveforms and their Oscilloscope Display 1960
Repairing Plastic Knobs and Gears
Tektronix Modification Numbering System 1968
Tektronix Standards: Abbreviations To Terms 1967
Tektronix Standards: Glossary of Technical Terms - Electronics 1967
Tektronix Standards: Terms to Abbreviations 1967
Troubleshooting Your Oscilloscope
Using the Oscilloscope as an Instrumentation Maintenance Aid 1958
- 7L12 Spectrum Analyzer Plug-in
- Casting a Replacement Knob
- 468 +5V Storage Supply
- 468 Vertical repair
- 465B and 468 Oscilloscope Horizontal Sweep Problems
- 400 Series Oscilloscope Vertical Attenuator Testing
- 400-series High Voltage Multiplier and CRT Replacement
- 475A / DMM44 Repair
- 4B53A Dual Time Base Repair
- Capacitance Keyboard Repair