Working 1050 but Track 0 Sensor Test Fails

[+Nezgar]

So I have a 1050 that functions reads writes & formats for regular use perfectly fine otherwise when in use, but I noticed it fails the Track 00 sensor test in the 1050 diagnostics software.

 

I read in a previous post by @phaeron : "...the track 0 sensor also activates on track 0.5 (!). This is documented in the Tandon manual and required for the Indus GT track 0 sensor adjustment test to pass."

https://atariage.com/forums/topic/256683-altirra-280-released/page/10/?tab=comments#comment-3643388

 

So the sensor is working, but I presume this means I need to adjust it. This issue is new to me, but it looks like it's just 2 screws to loosen to allow the sensor block to move until the diagnostics software likes it? Anyone else seen/adjusted this before?

[Rybags]

Possibly it does - the "half tracks" as we called them are in fact not quite half steps, probably more like 40/60% steps.

If the drive functions normally then probably best just left alone.  Nothing out there uses the part stepping and in fact the track 0 sensor will be active also if you step backwards to track -1 using the special diag commands.

 

An adequate T0 sensor test IMO would be to just - seek/read to some distant track, e.g. read sector 500.

Then without any other operation or removing the disk, perform a format.  The drive should seek track 0 then do the format, seek track 0 again and do the verify.  Then Dos would create the file structure.

Then remove and reinsert the disk.  Write a file to it and check it reads back.

More than sufficient activity there to ensure your track 0 sensor is operating properly.

[+Nezgar]

Thanks @Rybags. I went ahead and messed with the sensor position before performing your tests... The original green loctite was still intact, so in theory they had never previously been adjusted.. Once loosening, I could see that it was in the furthest position it could slide toward the front of the drive alread. I pushed it towards the back of the drive about 1mm and re-tightened it, re-ran the 1050 diagnostics and I now get a pass.

 

 

I then tried the head seek tests you mentioned after this adjustment. Seek disk to sector 600 (using EDDY.EXE), formatted the disk OK. remove disk, reinsert, back in EDDY, able write sector 10 and sector 600, and read them back no problem... so I think I can call this issue solved.

 

I guess I could move it back and see if the above process still fails.. nah.

 

PS: This drive has the Stock Rev K ROM, and the format routine formats track 0-39, then verifies from 39-0.

[Rybags]

Actually I think that's how all the 1050s do the format/verify.   I was thinking 810, which I'm fairly sure is the one that does 0-39 then seeks back and verifies the same way.

[+Nezgar]

2 minutes ago, Rybags said:

Actually I think that's how all the 1050s do the format/verify.   I was thinking 810, which I'm fairly sure is the one that does 0-39 then seeks back and verifies the same way.

Nope.

 

Sounds familiar, but I couldn't remember either... so I checked the Altirra hardware reference manual:

Maybe you're thinking of the 810 Archiver? Although it does a format+verify of each track before moving to the next, so at track 39 you would see a final seek to track 0 to write the DOS structures...

 

An interesting variant I have witnessed is the Speedy 1050 - unlike all other drives, it starts the format at track 39, and formats+verifies each track towards 0. This is a *great* idea that would have saved some people from accidental formats, as the last tracks of the disk are least likely to contain critical data, giving a user a chance to turn off the drive or remove the disk in a panic, and have minimal data loss.

[Faicuai]

Very interesting, as I had to deal with this, but on my 2nd IndustGT unit (blue-color dip-switch panel).

 

I ran GT-DIAGS on the primary unit (red-color dip-switch panel) and it will pass Track-0 sensor test, without a problem. However, ran the exact same test on the secondary unit, and not only did NOT pass, but it made a notorious, dry "tak" sound when reaching Track-00 from an N-to-0 stroke. The primary unit never did such sound.

 

As it turns out, it occurred to me to simply fire GT-Diags Track-Seek routine on an auto-loop, going from 5->4, 5->3, 5->2, 5->1 and then 5->0, and lo-and-behold, when performing the 5->0 test in auto-loop, it was all "tak" mayhem.

 

So I decided to adjust the track-0 sensor per the service-tech. manual, as well as GT-DIAGS report, and, not only the "tak" disappeared, but track-0 sensor test passes time after time, no matter how many times I test. In fact, the "acid" test (1->0 track-jump on auto-loop), passes smoothly and with little audible noise. It is actually impressing to see it, in action.

 

FYI, both drives perform essentially the same, with or without the track-0 adjustment done (e.g. I could never get them to fail, in any of the test or every-day use operation they are subject to).

 

Cheers!

Edited November 25, 2019 by Faicuai