Janome 6260qc - Need help.
Took bobbin "stuff" apart to clean. Put everything back together and now when I lower the needle, it crashes into the white metal plate under the bobbin case.
I've changed needles; rethreaded; took everything apart again to see what was going on and the needle lowers/crashes into this white metal disk. It's like the needle is too long, but its the same needle I used originally. Mother's day gift from son about 5 years ago and I love it - what do I do to restore Queenie to her thrown? Thanks friends

Sounds like you put it back together incorrectly. Get out your owners manual and make sure you've put the parts back in the correct spot.

one time I didn't have the needle all the the way up where it should be before I tightened the screw. I thought I did until I redid it.

Most likely this is true, I had that happen with my babylock espire when I put a different needle plate on I put it on in the wrong order, go figure didn't think it made a difference well after an hour of FMQ frustration, bobbin thread kept nesting and jamming, I read my manual, took it all apart and put it back together the correct way, sewed like a dream 2 minutes later