You can get the service manual from here:
http://bama.edebris.com/download/tek/465b/465b.pdfIt can be fixed, but oscilloscopes are very dangerous to work on if you are not experienced. The voltages to the oscilloscope tube are extremely lethal, and if you have no trace on the screen, it is possible there is a problem in the tube or in the high voltage electronics.
And you will probably need a working oscilloscope to find the fault in this one. It is just not the kind of device you can learn on. The fact it has broken buttons makes it worse.
Selling it for parts and starting off buying a working oscilloscope is not a bad idea.
It is just possible that the 465B works, but you just have the wrong settings. Post a clear picture of the front panel to this thread and we can check on your settings.
The trigger should be on auto. Intensity Timebase to something like 1mS. Delayed timebase not enabled. Does it have a "Find Trace button"? otherwise make sure the A channel is selected, and turn both the horizontal and vertical position knobs to see if you can find a trace.
Richard.