68k Mac diagnostics?

Hello all, I have a Quadra 700 which I've mentioned before which is in a poor state. I've finally gotten it to power on with a replaced power supply, but it dies with the chimes of death at various points before and after the boot chime; it never appears to initialize the video. I'm aware that the Q700 is quite reliant on the monitor sense pins, so I'm using an Apple 12" RGB monitor that I've verified working on an Apple IIgs. Since I can't see any video (there is no activity on any of the pins on the monitor port, not even sync pins), I'm wondering if there's another diagnostic tool that can be used aside from building something to hook into the '040 PDS and attach to a logic analyzer. I suppose it would be too much to hope that it can be made to spit something out on a serial port? The fact that the chimes come at different points in the process, and that it seems to change when I poke things on the board, leads me to believe it may be beyond help, but if there's something simple I can do to check it out, I'd be glad to. I've already tried swapping out for a known-good '040 and removed all the RAM (so it runs on internal RAM) to no avail. - Dave