Amiga Test Kit floppy read fails, yet drive apparently works

[Turrican_3]

Hey there,

while trying to debug a (different) floppy disk drive issue I've recently talked about in another thread, I resumed an old TEAC FD-235F-112-U. This unit was originally an external drive with some electronics added, but many years ago I got rid of the latter due to a failure I was unable to diagnose.

But back to the drive.

It apparently works perfectly fine when reading disks (I haven't tried writing yet), yet Amiga Test Kit floppy "Read" function fails, stating it can't read track 0. I've already cleaned the connector and the disk/write protect detect switch with IPA for all it's worth.

I'm 99.9% sure it's an issue of this specific drive because I own two other mechanical drives that do not show this error on the very same Amiga.

Should I bother? And if so, which further tests should be made?

[Leon Besson]

What does the calibration test show? Have had some weirdness like this with various floppy drives. Think it depends on the floppy disk and what drive it was written to.

[Turrican_3]

I'll check tomorrow and report back. Thanks!

[Turrican_3]

Ok I think I stand corrected, there's something very weird going on here but unfortunately I'm not knowledgeable enough of the Amiga floppy interface workings...

First, the calibration thing... fails horribly as well!

Track 0 shows a row full of "XXX..."
Track 39 and 79 shows a row full of "---..."

But that's not all.

I have yet to understand if it's reproducible, but it seems I need to insert an AmigaDOS standard disk before being able to have the drive work as intended. Otherwise the drive makes the classic three clicks, shows a DF0:??? icon/text and refuses to boot if I reset the Amiga. If I insert an AmigaDOS disk FIRST instead, the next disk will boot as usual.
(please note this system is currently equipped with an ACA500Plus, so I usually end up being in a WB3.1 environment if DF0: fails to boot)

What gives?

[cpiac64]

Ciao, i have write a guide for alignement on italian forum

you need use a floppy working 100% working like a original workbench

[Turrican_3]

Thanks mate, but I'm not sure it's an alignment issue, otherwise I suppose the drive would *always* fail, wouldn't it?

[hooverphonique]

Did you verify the track 0 switch works?

[Jope]

Maybe start by lubing the head carriage rail in your floppy drive (sewing machine oil and only a tiny bit), then drive the head between 0 - 40 - 79 a few times in Amiga Test Kit's calibration view.

[Turrican_3]

Originally Posted by hooverphonique

Did you verify the track 0 switch works?

I believe it does: checked with both DriveTest (Aminet) and Amiga Test Kit, signal appears to be consistent. I'll doublecheck though just to be on the safe side.

Originally Posted by Jope

Maybe start by lubing the head carriage rail in your floppy drive (sewing machine oil and only a tiny bit), then drive the head between 0 - 40 - 79 a few times in Amiga Test Kit's calibration view.

Will try this as well.

[solarmon]

What version of Amiga Test Kit?

What do you mean by "It apparently works perfectly fine when reading disks" - using what disks?

What disk are you using to test with Amiga Test Kit? Use a known working, preferably an original disk, AmigaDOS disk - like a Workbnech disk, or magazine coverdisk.

[Turrican_3]

Originally Posted by solarmon

What version of Amiga Test Kit?

I'll check and report back later.

What do you mean by "It apparently works perfectly fine when reading disks" - using what disks?

Basically, everything: first and foremost the Amiga Test Kit disk, but also original games on both standard AmigaDOS and "nodos" (Turrican2 for example) formats.

What disk are you using to test with Amiga Test Kit?

I usually check with the Amiga Test Kit disk itself: while I'm not 100% sure this is the correct procedure, since with the other 2, known working floppy disk units (1 Teac, 1 Panasonic, took from an A500 and A600 respectively) properly pass both the Read disk and Calibrate tests with this disk I've always thought there was no point in using a different one. Hopefully this isn't a major assumption fail...

[solarmon]

How was the Amiga Test Kit floppy disk created? Was it created on a different drive from the suspect one that you are testing?

[Turrican_3]

Yes, it was created on a different drive.
I'm basically 100% sure because this floppy drive has been sitting unused for years.

[solarmon]

OK, if you are confident that the drive used to write the ATK disk is good and well aligned, then there seems to be a slight difference in alignment between the two drives. Try doing the ATK alignment test on other known good AmigaDOS disks (but not written by the other drive), preferably an original Workbench or magazine coverdisk.

[Turrican_3]

Reporting back.

First, ATK was version 1.4, but I downloaded the latest available (currently 1.18)

Chose to write the updated ATK adf with the allegedly misaligned drive.

Here's the arguably interesting part.

1. while still inside the Workbench environment, the drive suddenly (with NO disk inserted) made a few clicks, turned its builtin LED on and a DF0:??? appeared

2. fired up ATK 1.18; head alignment still fails the way it did before (XXX on track 0, --- on tracks 40 and 79) BUT if I fiddle a bit from within the signals test page moving the head forward and back and leave it at track 0, head alignment test is OK at track 0 immediately afterwards; track 40 and 79 still fail though, and fails again as soon as I go back to track 0 (this is true regardless of the disk used, i.e. it leads to the exact same behaviour if I put a known good AmigaDOS disk or the freshly written ATK 1.18 disk)

3. ATK 1.18 Read disk test - which seems a fair bit different from 1.4 - now shows a bunch of red uppercase "B", plus many red "-" symbols


Now, I would think had it been a misalignment issue surely the drive would be perfectly able to read any floppy it has written, but show issues with others, right? Plus, that DF0:??? with no disk inserted reinforces my suspicion there's something wrong somewhere else, what do you think?


I'll put the oil on the rail later as I haven't picked it up yet.

[Jope]

Try the oil first before adjusting the alignment. :-)

[Turrican_3]

Just finished putting the oil and I... I think it's working?!

[Turrican_3]

Nope, now there's something that happens when I turn on the Amiga that prevents the drive from working. It almost always fails the first time (usual three clicks, sometimes more, as if the disk was not formatted or things like that) especially if the drive is empty when the Amiga is turned on... yet often works if I reset the Amiga or simply eject and re-insert the floppy. From then on, it will usually just work until the Amiga is kept powered on.

This is driving me crazy. :-\

PS: calibration tests on ATK are always fine though (as soon as ATK boots that is)

[Jope]

Will it make the three clicks on power up with no disk in the drive? That sounds like a sticky disk detect switch or a faulty CIA.

[Turrican_3]

No, just if/when I insert the disk.

When powered on with no disk you can only hear the usual Amiga click.

I can do a small video, perhaps it might help.