Defect Akai S900 display and floppy drive

When starting the S900 strange display appears on the lcd and it seems the Akai won't boot up

When opened up, I found a defective connection in the power supply:

I removed the power supply and soldered a new connection.
The S900 was live again!

But after some testing the floppy seemed not to be able to load more than a simple program from any of the floppies.
Two possibilities:
1) clean the drive
2) search for a replacement

to be continued