A quick update:
I fitted the new laser... and it fitted perfectly. It appears to be just right as a replacement! They all look brand new too, complete with little white boxes.
However, my FZ-1 still doesn't turn the disk so I think something else is wrong. I need a working drive to check against. I measured 1KOhm across the potentiometer... perhaps this is wrong (I have no idea what it should be), so I tried 500 Ohm and 1.5K but no difference.
As soon as I can find another drive mechanism I can test the laser but at the moment it looks just right
The first laser I did did nothing (same as my old one)
The second span the disk! But didn't boot anything.
But the third... the third is running like a champ.
I suspect the others may be persuaded to run with the correct potentiometer setting. Laser 3 is set to 600 Ohms at the moment. Road Rash still doesn't work properly, though, so the disk must be bad. I've also noticed that some of the flaws in decoding the Powers Kingdom movie are now gone, so this one is definitely stronger than my original laser.
What I'm going to do, I think, is test all the lasers I've got and put the working ones on my shop. If I find many don't work, of course, I will
have to increase the price to recoup my costs, so the final cost depends on how many work. It may be that only one in three work, it may be that this one is the only one that does work, or it may be that I'm just better at fitting lasers now.
Time will tell!
In the meantime if anyone wants to try a laser let me know....
Just tried Laser #4. Worked perfectly, first time. I must be getting better at fitting these things.
This one had a resistance of 711 Ohms.
Surprised people haven't commented on this thread, actually. I would have thought this would have been of great interest to 3DO owners...?