I viewed your videos with great interest in that I also have a Tek 465/DM44 that I'm in the process of restoring. And the issues I've had are quite different from what you had and I'll share what I found so far. (It's not done but real close)
This 465 came my way a few months ago from a Ham who was selling most of his equipment. I noticed right away that it was in pretty poor shape and had apparently been stored in a damp environment. But the price was right and I decided to give it a shot. First thing I did when I got it home was give it a good cleaning. I got it to the point where it looks decent but you can still tell it's lead a rough life.
First attempts at power up did not go well. Line fuse blew immediately. I found the +15V supply solid short to ground. Tantalum caps C4498 and C891 were shorted. At that point I just replaced the ones I found shorted. Future plans are a massive tant cap change.
But this did not fix the supply issues and the line fuse continued to blow immediately. The +110V supply was shorted to the +55V reference supply. Extensive carnage here. VR1515 and CR1514 shorted. R1517 burnt. And finally Q1516 and Q1518 shorted. Once all the parts were replaced the scope finally powered up but with a very weak trace.
Once I adjusted the +55V reference to nominal, adjusted the HV to spec, and set the CRT bias the trace intensity is now normal and bright. Applied test signals to channel 1 and 2 and it was immediately apparent that there were issues with both attenuator switch decks on the vertical board.
Both Volts/Div switch decks were extremely noisy and it was apparent that I would have to pull the vertical board to clean them. It was not fun pulling that board and disassembling the switch decks. But once I got it back together Channel 1 was fine but now I had no trace at all on Channel 2. After a lot of troubleshooting and head scratching it turned out to be nothing more than dirty transistors sockets. Dexoit worked wonders here. Channel 2 trace was restored but still had issues with the attenuator not tracking correctly.
More troubleshooting and found the cause. Channel 2 X10 attenuator assembly is shorted. I have a new one on order. Plus new BNC's for both channels. Channel 1 BNC is very worn and intermittent and Channel 2 BNC has an internal short and randomly switches by itself from X1 to X10.
Here's some pictures it currently pending replacement of the attenuator and BNC's. I also spray painted the case which really helped to clean it up. And finally, I'd like to thank fellow member bd139 for his suggestions/help in troubleshooting.
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