what I have found out when I was fixing my 3do FZ-1 machine.
Bought one Fz-1 machine from ebay, had numerous problems
and I will list them here and the following sollutions for those problems
Notice!
I made a little webpage for these repair instructions
where I describe the whole process in more detail
with pictures.
http://www.datacentra.net/other/3do/index.html
Problem #1
Disc wont spin and the laser will not initialize
found out that in my 3do the laser's pickup motors
plastic gear was broken, due to design fault the gear will over
time wear out and snap. that causes the motor to jamm and the
laser will not move to it's starting position and the system will not initialize.
replaced the worn gear and presto! problem #1 solved.
The laser's wormrail "pickup rail" motor is located at the back of the
cd drive, it is held down by 2 screws. it is the motor with the orange and brown wires.
NOTICE
Also if you have a broken disc spindle motor you can replace it
with standard 5.9v dc cd spindle motor, these can found in playstation 1
laser assembly. My 3DO works just fine with this motor.
Problem #2
Disc keeps grinding on the disc plate, hence the disc wont
spin up right causing it to vibrate and reflect distorted image back to the
laser.
sollution:
cut out 4 small pices of electrical tape and place them on the disc plate.
this causes the discplate to have more friction thus stopping the disc from slipping and grinding.
problem # 3
laser unit is worn out need to be replaced but cannot find the
correct laser unit.
the panasonic 3DO FZ-1 uses SANYO SF-92.5 laser pickup with 11 / 4 pin connectors with dual short cables!!.
looks like this

*UPDATE*
It seems that the regular OEM Sanyo SF-92.5 4/11 pins laser
design has been changed from the original Sanyo specs
so it wont fit 3do fz-1, but the good news is that they are still
making the old version wich is called Sanyo SF-92.5 4/11 pins "dual short cable"
I have sent numerous emails to every source I found that have once
sold this item for inquiry.
-Clive