465 Tear-down Guide
Learn and know how to identify and properly discharge high voltage circuits.
Do not touch live circuits!
Do not remove shields without taking all precautions.
Proceed at your own risk!
The first 465 I picked up was a working scope, but once I had it home and on the bench it showed its age. It was clearly a workhorse, and was due the TLC I was ready to give it. I was ok opening it up and tweaking it, but there were some issues that required potentially serious surgery. I didn't have the courage nor confidence to break it down and get it back to working again. So I quickly picked up a second scope as a "parts" scope, to both provide any parts and as a guilt free tear down practice unit. And if I could get it working again then I'd feel better about risking breaking the first scope.
Since this was my first experience at tear down of any oscilloscope I wanted to capture the difficulties and unknowns a novice experiences. I took copious notes and pictures. While there are many tear-down stories and pictures online, there wasn't quite the clarity I would have liked as I worked through the process. It's not just nerve wracking to blindly work out how to break something down, but the risk to expensive or permanent damage is real. I hope the following guide provides the clear descriptions and images necessary for any novice to get down to the various parts and components necessary to bring these old scopes back to life.
This guide is a bit incomplete as I have not gone so far as to remove the transformer and A9 Interface Board. Doing so requires some special tooling for removing pins of the regulator range selector, and the unsoldering of significant wiring. For me there wasn't much return for the effort as tearing down as far as this guide goes provides good access to the majority of components. Only having access to the backside of the middle of the A9 board is restricted. Component replacement is still possible from the component side of the board.
It is also valuable to refer to the Tektronix 465 Service Manual. Section 4, Maintenance, has some component removal instructions. The Service Manual can be found on the TekWiki, and hard copies are generally available on eBay or other online resources. Also see the TekWiki 465 Repairs section. See Components and Parts section for information on finding replacement parts.
Some portions of the scope can be disassembled without regard to order. Other portions require disassembly of other components first. These will be noted as necessary.
Review of the 465 Service Manual Section 4 contains instructions for disassembly along with other important recommendations. For example, soldering techniques contains recommendations for wattage and cautions for sensitive circuits. Figures 1 and 2 at the back of the Service Manual provide exploded views of the oscilloscope's construction as well as parts lists.
First remove the case to gain access to the scopes internal components.
Vertical Preamp Assembly
The Vertical Preamp Assembly can be removed independent of other components. The assembly consists of the input attenuators A1 and A2, vertical amplifier and switching board A3 and the vertical mode and VOLTS/DIV switch board A4. The etire assembly is removed as one, then each board can be removed from the assembly independently. The A1 and A2 attenuator boards must be removed after removal of the A4 switch board.
The Trigger Board A8 can be removed independent of other components, but does involve disconnection of the power switch pushrod and switch assembly. The switch assembly can remain connected to the A9 interface board.
Sweep Timing Board
The Sweep Timing Board A7 can be removed after removal of the Trigger Board A8.