Fixing the disk drive on a 70FD

Disk drive issues are very common with MSX 2+ machines. Unfortunately that was also the case with my Sanyo 70FD. In most cases, the problem is with old drive belts and everything works fine after those are replaced. However, the 70FD disk drive does not have a belt so there was something else going on here. I could see that power was getting to the drive and I could also see that it was trying to read a disk (it would make a humming sound twice and then I would get the “Drive is offline” error message).

Here is how the drive looks like when opened:

Asking around the forums, I got a tip that the problem with these drives are usually with the endless screw (you can see it on the mid-upper side of the picture). Apparently that screw gets dry and that prevents the read/write head to move correctly. So what I did here was to first clean it (using a cotton swab and alcohol) and then I lubricated it with vegetable oil. I put eveything back together and I could hear the sound a little louder but still no movement. I then ran the following little utilities that basically make the motor move back and forward:

10 poke -609,201
20 for i=0 to 1439
30 print dski$(0,i)
40 next

10 poke -609,201
20 print dski$(0,0)
30 print dski$(0,1439)
40 goto 20

That did it! The read/write head started moving again and everything was working perfectly! For those cases where the drive is really damaged, one of the few resellers out there is ditta bass. There is also a more complex option to adapt a regular drive – you can find some info on how to do that here.

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