The same thing happened to my FZ10 and I ended up having to scrap it.
Check and make sure the spindle motor works by supplying it with low DC voltage. If it spins then its more than likely the laser gone bad. There are no drop in replacement laser assemblies for the 3DO.
The 3DO wont send the command to start the spindle motor until it can properly focus on the disc.
Actually here is one a drop in replacement lens.
http://www.ebay.com/itm/SF-92-5-4-11-PIN-Original-New-Sanyo-Laser-Lens-SF92-5-BMW-Mercedes-Panasonic-3DO-/120872471141?pt=LH_DefaultDomain_0&hash=item1c248f8a65
And yes my FZ 10 has the same one in it.
Ever since I found these I have been hunting for information just so we don't get our hopes up about a solution to the 3DO laser crisis.
I have some good news. The laser assembly in both the FZ-1 and FZ-10 is the exact same assembly of this I am 100% certain. Those and these are both Sanyo SF 92.5 Now for the bad news. These replacement lasers I found won't work. :'(
Reasons why,
1. Cable length. The connector cables are too long and allow some rather bad interference. That and the 4 pin end isn't right and will need modifying.
2. The side that connects opposite to the drives worm gear is measured at 3m, where as the originals are 3.5m
These can be made to work. With some finesse with a soldering iron and drill. You will need to de-solder the old four pin from the original 3DO laser. Then
CUT the 4 pin off the new one and solder the two together. Because the attached the magnets to the 4 pins in the new ones and soldering them will ruin them. Last but not least one of the cables has to be hard wired to a spot on the mother board. Oh yeah, and drill out the runners to 3.5m.
Figured I would throw that out there before someone bought one to find out the hard way, Unless you are sure of your skill with electronics that is.