I have a 7904 mainframe chassis minus the plug-in modules free for the taking - or you pay shipping. Parts or whole. Nice front panel, no buttons broken off. Worked up until a year or so ago - now when you turn it on it initially powers up fine but then after a few minutes the display is gone. Maybe a PS issue, but I have since replaced it with a smaller model and probably will never get around to fixing it. Let me know if you need parts or the whole - it is in Erie, PA if you were interested in picking it up. I'd hate to scrap it as it is still a useful scope if someone had the time to dedicate to it, but the reality is I have no time currently.
Thanks, Greg