maxtherabbit wrote on 2021-04-14, 14:46:

You sure you're using single step? Your photo says double step

Anyway I'd guess more likely a problem with the stepper based on those results

+1 on this

Is it seeking ok? Have you used it to successfully format a disk? (Which presumably then doesn't work on another computer) Does it need cleaning?

Robbo- take a blank disk or one that has nothing of value on it and try to format it in your drive. If the alignment really is the issue it will format and work fine. If you still get errors then something else is going on

@Inbetweendays: Yep makes sense thanks. If you see my post, tracks 0 to 66 show correct output and no errors. (sorry I mistyped this, track 0 show correct output, tracks 1 to 66 shows no match numbers in 4th column) But after that the rest of the tracks give no-match numbers in the 4th column. The floppy disk is a 720k DD disk and was formatted in an another machine with a 1.44mb drive using the /f:720k parameter to force 720kb. Is this fine for testing? When you mean "worm gear" do you mean conical adjustment screw?

***Head 1 has simular behaviour.

@maxtherabbit: yep. Image was an old image when I was messing with the step. Second test was on single step.

maxtherabbit wrote on 2021-04-14, 14:52:

Robbo- take a blank disk or one that has nothing of value on it and try to format it in your drive. If the alignment really is the issue it will format and work fine. If you still get errors then something else is going on

If I format the disk in the drive it formats correctly and I can copy files to it and read them. If I put this disk into another PC with a working drive I can't read the disk. Heads have been cleaned too.

***note, Ive edited my previous post as there was a typo.

robbo007 wrote on 2021-04-14, 15:54:

maxtherabbit wrote on 2021-04-14, 14:52:

Robbo- take a blank disk or one that has nothing of value on it and try to format it in your drive. If the alignment really is the issue it will format and work fine. If you still get errors then something else is going on

If I format the disk in the drive it formats correctly and I can copy files to it and read them. If I put this disk into another PC with a working drive I can't read the disk. Heads have been cleaned too.

***note, Ive edited my previous post as there was a typo.

Interesting. Can you perform the IMD alignment test using the disk you formatted in the 4865 and ensure that it passes on all tracks?

maxtherabbit wrote on 2021-04-14, 17:35:

Interesting. Can you perform the IMD alignment test using the disk you formatted in the 4865 and ensure that it passes on all tracks?

Yes, If I format the disk in the problem drive the XT can read and write to it fine and IMD alignment test works perfectly. If I format the disk in another PC (working drive) and run the alignment test I get pretty much everything after track0 showing that all the ID's don't match, ie 18 in the 4th column.

So my question is, do I run IMD alignment and on each track slowly turn the screw (indicated in my photo) until I get all the Id's matching on each track? Is that the way to align?

It's quite possible that once you get a track somewhere in the middle working ok, that the others will then all be good (or at least close), except track 0, and you can then adjust the track 0 sensor.

BUT... if it was me, I wouldn't touch it until I get a real 720k disk (ideally an original software disk) that you've verified as good on the other machine. Maybe the 1.44mb formatted to 720k is ok to use - it's not gonna suffer from the same problem as formatting 360s in a 1.2mb drive - but to me it's a bit of an unknown.

InbetweenDays wrote on 2021-04-15, 09:57:

It's quite possible that once you get a track somewhere in the middle working ok, that the others will then all be good (or at least close), except track 0, and you can then adjust the track 0 sensor.

BUT... if it was me, I wouldn't touch it until I get a real 720k disk (ideally an original software disk) that you've verified as good on the other machine. Maybe the 1.44mb formatted to 720k is ok to use - it's not gonna suffer from the same problem as formatting 360s in a 1.2mb drive - but to me it's a bit of an unknown.

Right. I grabbed my original copy of Bitmap Brothers Magic Pockets (720KB disk). On my other Pc I fired up IMD and tested the disk on a working drive. No problems. Disk shows all tracks correctly.

On the XT I used the same disk on the "faulty drive" and track 0 is fine but all other tracks after it display some ID's which match and others with dont match. Each track seems to have different results. I can't see a pattern.

perform the alignment at track 40 and then confirm it's good on the rest of the surface

use a retail disk to reduce the tolerance stacking error potential from a disk created on a drive of unknown alignment accuracy

maxtherabbit wrote on 2021-04-15, 12:51:

perform the alignment at track 40 and then confirm it's good on the rest of the surface

use a retail disk to reduce the tolerance stacking error potential from a disk created on a drive of unknown alignment accuracy

ok, to preform the alignment I need to slowly turn he screw until I start seeing good results with track 40 selected? Should I turn clockwise or anticlockwise?

There's no real way to determine that other than trial and error. Once you get IMD reading the sectors from track 40 reliably, try to find a center point between where errors appear in either direction and lock it down there

Rock and roll guys. Got the sucker working 😀 wohooooooo!!!! After a few "tweeks" I managed to get it working, reading floppies, writing to floppies and even formatting floppies. I tested on both computers to make sure. All good.
Amazing... Thanks for all the help. A real life saver. I'm so thrilled 😀

That's awesome... well done and glad to hear you got it working nicely!