How to align an Amiga disk drive?

[Amiga1992]

I know Overdoc (hardware meister uber alles ) has managed to realign an Amiga disk drive... How do you do it? Any docs I can find on the net?

A friend has this drive that denies to read crap.. It might as well be a bit dirty... what do you guys suggest?

Cheers,

[Overdoc]

Thanks for the kind words
I wish I really were, because then I could fix that A-1200 I bought for about 35 US$ last weekend....

Now, I have done this only once and I am not sure if it will always work. There are also some differences in various drives ( I know Chinon FB354, Epson SMD 340 & one Teac drive ), and it might also be possible that the drive's mechanics are worn out and don't work precisely enough any more. In this case aligning wouldn't help much...

Ok, basically you have to boot an old version of X-Copy, which has the 'Checkdisk' option in the tools menu. If you have Kick2.0 and above you can boot from the external drive, but if you only have Kick 1.3 then you should remove the external drive from it's case and hook it up as internal. Then connect the dead internal drive to the external case and boot X-Copy.

Now have a look at the dead drive and you will find a sensor at the back of the drive ( near the motor which drives the spindle or tooth-rack to position the R/W head ). This sensor is usually mounted to a very small board which is fixed to the chassis of the drive with 1 or 2 screws. ( I think the Chinon drive has it fixed to the drive's mainboard ).
Now, put a known good disk in the bad drive ( e.g. original Workbench, no copyprotected gamedisks ! ) select the bad drive and 'Checkdisk' in X-Copy, set 'Side' to 'Lower' only and perform a checkdisk.
If you get some errors then the lower head is misaligned.
To align it, loosen the screw holding the sensor's board, move the board a tiny little bit ( this needs absolute precision !! Just move it a quarter of a millimeter or so ), tighten the screw again and perform a checkdisk again.
Now do this procedure over and over until you have found a position where you don't get any readerrors, even after multiple checks. ( This can take a long, long time.... ) Be aware that the right position should not be away from the original position too much. So carefully remember where the board was fixed before you loosen the screw the first time !

Ok, after that the lower head should be aligned ok.
Now, set X-Copy to 'upper side' and perform a checkdisk again.
If you are lucky then also the upper head should be aligned well by now. If not, then locate 2 screws where it is fixed to the lower head and do the same procedure as you did with the lower head with the upper one again.
In my case I didn't have to do this, but I also read somewhere that this can also be accomplished by carefully looking at the upper heads position and then position it exactly over the lower head, just by eye-measure.

Ok, I hope this makes sense and I wish you good luck
If you have any further questions just ask before you might do something wrong. I will try my best to be of help

Cheers

[Amiga1992]

Thanks heaps for the info! will try it out with this guy's FDD. It should be one of the drives that come originally with any A500, Chinon or Panasonic perhaps?

He has no external drive but I Can take my 600's FDD and connect it to his 500 to boot up xcopy. Or perhaps I can connect his FDD to my 600, it would be easier (I can boot xcopy from HD)