I believe Lisa uses fonts stored in RAM, so unless the CPU is running properly and power on self test completes, the screen will be filled with a random pattern which won't move, that is it won't roll, flicker, or tear like an old TV with misadjusted horiz & vert controls. If the screen is stable, then probably power is OK, the I/O board is at least partially functional, and the CPU is not running. CPU problems can be bad ROMs, chip pins oxidized in their sockets, chips loose in their sockets, failed capacitors, etc. If seating all the chips into sockets and looking for evidence of leaking goo from any parts doesn't turn up anything, then you will probably need to troubleshoot it by substituting known good parts. The floppy drive almost certainly will need a cleanup and lubrication at its age. The computer is old enough that it would be pretty remarkable if it DID run.

Since nearly all Lisas were converted to Mac XLs, an original Lisa is more interesting to historians, because very few people have seen Lisa software, and how it differs from Macintosh.