General Category > Lisa Troubleshooting and Repair

Plan for Problematic Profile (+ some other word beginning with P)

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cheesestraws:
It sounds more... abrasive than your NNNNNNNNNEEEEEEEEEEOOOOOOOOWWWWWWWWWWNNNNNNNNNN, but of course onomatopoeia is not a precise science.  Perhaps the best option is just to "run it in" for a while, see if the motor returns to its duty, and apologise profusely to the other half who shares the office with me.

stepleton:
There may be little left to lose, but you may wish for a third opinion from someone who's less cavalier than I am about this (and who perhaps has a better idea of what you're dealing with). Good luck and I hope it doesn't throw a rod!

rayarachelian:
These might (or not) help:

* https://www.youtube.com/watch?v=Ur1hg0SUEWA
* https://www.manualslib.com/manual/1173380/Seagate-St-506.html
* http://www.minuszerodegrees.net/manuals/Seagate/Seagate%20ST506%20-%20Service%20Manual%20-%20May82.pdf
* https://www.youtube.com/watch?v=kwGuNHf6KxY - (as LLF on a PC, but obviously don't do this from a PC)If you do open it up, and probably that should be the last resort option, make sure you're in a room that has little dust. One thing you might do is bring it into a bathroom after running the shower for a bit to get all the dust to drop down to the floor, and then let the bathroom dry up a bit before you do open it.
You want neither high humidity nor dust. Running the shower should help get most of the dust in the air down, but the humidity isn't great either so wait for it to dissipate too. If your bathroom has a fan, use it.

Once you open it, if you see streaks on the media, that would indicate a head crash and would explain the high level of noise. Let's hope this hasn't happened.

patrick:

--- Quote from: cheesestraws on March 04, 2021, 05:35:35 pm ---3. Try to find a working ST506/ST412 (?) and try to do surgery on it to put the Apple board on the bottom of it.  I currently have no idea how to do this, nor how to do the required low level formatting when it is done.

--- End quote ---

You can use an ST-412 as a direct replacement for the ProFile 5MB drive mechanism. Just replace the analog board, i.e. keep the one that came with your ProFile. ST-412 is the drive that was used with the IBM PC/AT, so it is fairly common.

An ST-506 mechanism will also work. However, Apple used their own stepper motor with a smaller step angle. With the stock motor, the ProFile would only access every other track. Therefore, you will need to disassemble the drive and install the old stepper motor. This requires a clean room area.

For the 10MB ProFile this is the only option -- you have to use a ST-412 together with the Apple stepper motor.


Concerning the bearing noise: Sometimes it helps to run the drive upside down for a while. This distributes the grease in the bearings. When upside down, the disk read heads must be on the parking track and must not be moved. To ensure this, you can disconnect the data cable from the disk and leave only the motor cable connected. Then cover the disk with a newspaper to keep it nice and warm, and let it run for a while.

compu_85:

--- Quote from: patrick on March 05, 2021, 02:52:07 pm ---...

You can use an ST-412 as a direct replacement for the ProFile 5MB drive mechanism. Just replace the analog board, i.e. keep the one that came with your ProFile. ST-412 is the drive that was used with the IBM PC/AT, so it is fairly common.

An ST-506 mechanism will also work. However, Apple used their own stepper motor with a smaller step angle. With the stock motor, the ProFile would only access every other track. Therefore, you will need to disassemble the drive and install the old stepper motor. This requires a clean room area.

For the 10MB ProFile this is the only option -- you have to use a ST-412 together with the Apple stepper motor.


--- End quote ---

I've fixed 4x 5Mb ProFiles with PC ST-506 mechanisms. I've not observed a stepping motor difference between the mechanism in the Profile and the PC drives. The 506 mechanisms I've used were produced from 1982 to 1984, so it doesn't seem like there's an early / late production difference. (The 1982 mechanisms had the mechanical spindle brake on them, instead of the electrical brake like the later drives!)

I've also fixed a 10M Profile with a PC-412, which worked properly. As a fiddle-fart test, running the 10m formatting software with a PC / Apple 5M disk fails when the stepper hits its end stop half way through.

That said, ST-412 disk mechanisms seem to be easier to find than 506s. I happened in to a box of "dead" 506, probably packed away in the late 80s. I'm guessing there was some fault in the Seagate PCB, because when fitting them to Profiles they worked fine.

-J

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