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3.5" SCSI Microscribe - DO NOT ROTATE INTERRUPTER

M

mhristau

New Member
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Apr 4, 2016
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2
Seems that a couple years ago when checking my Mac SE/30 I recall that my finger reached out (finger has no eyes and cannot read) and touched the interrupter stepper motor shaft.

Does any one know what the correct startup position is?

It starts up with couple chirps, the interrupter moves and LED goes out...

image.jpg
 
It typically won't harm the drives. Manually moving the head rack back and forth is an old trick to free a sticky head rack.
 
It calibrates itself when it powers up - that's why it does the arm back and forth motion.
You touching it wouldn't have caused any problems with positioning.
 
Thanks for you replies.
Then I guess the drive is ready for the recycle bin and to be replaced by one of those powermonster ii 2.5 scsi to cf adapters?
 
If it formats, use it. No point throwing out stepper motor drives at this point in time if they are still useable.
 
Those miniscribe drives have a terrible track record for "stiction" where heads stick in place. I have to rotate mine EVERY single time I power it on or the heads won't break free, I see little point in using these drives for anything other than just to hear the fantastic sounds they make, I certainly don't trust them to hold any data. I've upgraded to modern ultrawide SCSI drives in almost all my old Mac's, well somewhat modern, I suppose some of my 9.1GB drives are getting up there in age, I really wish the SCSI2SD and PowerMonster converters weren't so dang much money, I would buy a case of them lol.
 
I wouldn't toss it without running some more tests. I'd attach that drive to a good Adaptec card on a PC and run it through the card's low level format test, and run various other test/diags on it. (Even if that drive doesn't support real LLF, that should zero everything out and freshen everything up.)

Although if your SE/30 is something you want to boot up regularly, as RWallmow suggests, it might be time to retire the drive in favor of something larger.
 
glitch said:
It typically won't harm the drives.
Click to expand...
Well, if you rotate the interrupter by hand on a non-running drive, you'll scratch the media surface because the heads are touching it. This might only be a problem when the heads are outside of the landing zone, but most of the time you can bet they are.
 
Timo W. said:
Well, if you rotate the interrupter by hand on a non-running drive, you'll scratch the media surface because the heads are touching it. This might only be a problem when the heads are outside of the landing zone, but most of the time you can bet they are.
Click to expand...

You can, but I haven't seen severe (as in bad sectors or visible damage) caused by it. The head is flat and lays very softly on the surface.
 
Timo W. said:
Well, if you rotate the interrupter by hand on a non-running drive, you'll scratch the media surface because the heads are touching it. This might only be a problem when the heads are outside of the landing zone, but most of the time you can bet they are.
Click to expand...

Never happened yet on any of mine, I have rotated full range, stop to stop on a few of my Miniscribes, no damage yet. However that may not be the case for all brands, the only other stepper motor drive I have is a Seagate and it's still working fine, never had the need to rotate it by hand.
 
RWallmow said:
Those miniscribe drives have a terrible track record for "stiction" where heads stick in place. I have to rotate mine EVERY single time I power it on or the heads won't break free, I see little point in using these drives for anything other than just to hear the fantastic sounds they make, I certainly don't trust them to hold any data. I've upgraded to modern ultrawide SCSI drives in almost all my old Mac's, well somewhat modern, I suppose some of my 9.1GB drives are getting up there in age, I really wish the SCSI2SD and PowerMonster converters weren't so dang much money, I would buy a case of them lol.
Click to expand...

Hi, I sell the SCSI2SD adapters on eBay, Amazon, and elsewhere, and I don't think $60 plus shipping is really asking terribly much for it. You can disagree, but I would encourage you to sit down, add up the cost of the parts alone, and then add another ~$7-10 for the PCB, depending on the volume of PCBs you're ordering. The through-hole assembly is done by hand at the factory, as well as the initial programming of the bootloader. Everything is then tested. Keep in mind you'll basically never need to replace a SCSI2SD due to failure of the unit itself.
 
aperezbios said:
Hi, I sell the SCSI2SD adapters on eBay, Amazon, and elsewhere, and I don't think $60 plus shipping is really asking terribly much for it. You can disagree, but I would encourage you to sit down, add up the cost of the parts alone, and then add another ~$7-10 for the PCB, depending on the volume of PCBs you're ordering. The through-hole assembly is done by hand at the factory, as well as the initial programming of the bootloader. Everything is then tested. Keep in mind you'll basically never need to replace a SCSI2SD due to failure of the unit itself.
Click to expand...
I was never arguing that they are not worth their asking price, I am just a cheapskate and have been using FREE 9.1, 18, 36, and 75GB SCSI drives, and when you have like 20 systems with SCSI drives in them, $FREE * 20 is A LOT less money than $60 * 20 ;)
 
I think the general idea is that you don't want the disk head touching the disk surface except in the landing / park zone. If you spin the interrupter around by hand with the disk off you are moving the head across the data area of the disk. Normally when the head is in those areas it is flying on the cushion of air created by the spinning platters.

It would also be bad if you moved the heads around by hand while the drive was trying to write something.

Just poking it with your finger is not going to kill the drive.

-J
 
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