I got my hands on a non-working, but inexpensive enough to gamble on, Tektronix 464, assuming I would have to do something to it, but since I the screen came on, and I saw a dot, I assumed it would be in the low voltage section that I would find the problem. Once I got it home and opened up though, I found a wire that looked like it got a bit warm, so I started following it, but it went under the top high voltage shield. I opened up the top shield, and started seeing major smoke residue all over the place. It was bad enough that it made it difficult to find the first obvious signs of damaged components, which were on the fan control board. The smoke had just billowed up into that high voltage section. Realizing that the fan being bad would not cause there to be no trace, I started looking deeper. I found more signs of smoke damage coming out of the CRT housing.
Needless to say, at that point, I didn't feel up to pulling it apart far enough to see what smoked inside that compartment. I'm not sure if the two problem areas are connected. It could be that the fan blew, and someone kept using it and it overheated and blew something else.
Anyway, It's a pretty old scope, so my interest in repairing it doesn't extend to tearing it down that far, so I am willing to send it off free to someone who is willing to pay shipping, or wants to pick it up in Peru, Indiana (USA). I considered putting it up on Ebay for parts, but figured there might be someone here that could find use for it.
I've attached pictures of the damage I have found.