Old oscilloscope help: ideas sought

Back in the late '70s and early '80s, I used a particular oscilloscope, a "TYPE 304 H" "CATHODE-RAY OSCILLOGRAPH" from "ALLEN B. DUMONT LABORATORIES, INC., PASSAIC, N.J., U.S.A." (all quotes come from the front panel markings). It worked fine then. After sitting idle for years - probably at least a decade - I've got my hands back on this 'scope. It doesn't quiet work, but appears to be close. It's an entirely vacuum-tube design; even the power-supply rectifiers are valves rather than semiconductors, and all the wiring is point-to-point, with terminal strips used as necessary and most components self-supported by their leads. (I mention this to give some idea of its age.) When I turn it on, it appears to power up. All the filaments light as far as I can see (the one I can't see is the CRT, and since I get some light on the screen under some circumstances, I infer its filament is working too). But I can't find the beam. I've set both X and Y selectors to "off", which (based on my past experience with this 'scope) should give me a single stationary dot. If I crank the intensity all the way up, I get vague shadowy patterns of light on the screen, but no matter how I play with the X and Y position controls, I can't get anything definite. The Y position control does something; the X position control does not, as far as I can tell from watching the screen. What memory I retain (which may be wrong) indicates that this display syndrome is typical of a beam which is far off-screen in one direction or another, but doesn't give any hints for what to do if the position controls don't work. Any thoughts? I googled, to no avail. Since the wiring is point-to-point, I could trace out a schematic. I will if I have to, but I'm hoping that the above symptoms is enough for someone to point me in a useful direction to look for the problem. Unfortunately I have only minimal test equipment available - a moderately-decent electromech voltmeter is about it. Since the X position knob does nothing, I speculate that that pot has gone bad and is, in terms of the circuit it controls, always hard over against one margin. Does this sound plausible? I may try to find the deflection electrodes and apply the voltmeter to them, if it has a suitably high range (I'd not try it unless it has a range of at least a kilovolt). Yes, it'd load the driving circuit more than it's designed for, but glassfets are mostly pretty resistant to that sort of thing, and the loading alone may well bring the beam back on the screen if that's what's wrong. /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse at rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B