Unidisk 5.25 vs. the platinum version

Steve Nickolas

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Dec 7, 2018, 10:23:41 AM12/7/18

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Someone linked me a copy of the manual for the //e card and it
specifically mentions not to use the beige Unidisk (this is kind-of
academic since I don't have any Y-cables yet let alone a working LC,
although the latter I've ordered).

What would be the difference between the platinum 5.25" drive and the
Unidisk that would cause issues? I seem to recall similar warnings with
the GS. (My Platinum came with the beige drives.)

-uso.

Tempest

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Dec 7, 2018, 11:38:49 AM12/7/18

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Well according to the wiki

>>Apple UniDisk 5.25 (A9M0104)
The UniDisk 5.25" disk drive is compatible with all Apple II models except the ROM 03 IIgs, IIc Plus and LC //e Card. These require the AppleDisk 5.25 (A9M0107) or compatible drives.

I never knew that there was a difference between the two. I swear I'm using a Unidisk 5.25 with my ROM 03 IIgs, but I need to check on that.

Steve Nickolas

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Dec 7, 2018, 12:48:58 PM12/7/18

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They at least look the same to me, I would've thought the only difference
was the color. (Just checked and mine are absolutely A9M0104. I don't
see a diff in color from my Plat or my Mac keyboard, but that might be due
to discoloration. And I have no intention of retrobriting them ;).)

(BTW, found my mouse while looking at the drives.)

-uso.

qkumba

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Dec 8, 2018, 6:34:11 PM12/8/18

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Always in the last place that you look... unless you keep looking afterwards just so that you can say that it wasn't in the last place that you looked.

Steve Nickolas

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Dec 8, 2018, 10:09:12 PM12/8/18

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A quick google suggested something to do with voltages. (I guess like how
you need a voltage downstepper to use a 486DX5 in a motherboard not
designed for it, even though it is physically compatible with the DX/33,
DX2/66 and DX4/100.) I don't see how that should matter.

-uso.

Tempest

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Dec 9, 2018, 8:26:59 AM12/9/18

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I just double checked and I am using Unidisk 5.25" drives with my IIgs ROM 03 with no problems.

waynej...@gmail.com

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Dec 9, 2018, 4:01:29 PM12/9/18

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On Sunday, December 9, 2018 at 5:26:59 AM UTC-8, Tempest wrote:
> I just double checked and I am using Unidisk 5.25" drives with my IIgs ROM 03 with no problems.

APPLE 3.5 DRIVE SPINNING PROBLEM

In certain configurations a spinning problem may occur when Apple 3.5 drives and UniDisk 5.25 drives are daisy-chained and connected to an Apple IIgs.When this happens, one or more of the drives suddenly start to spin and can no longer be accessed. The problem only occurs on Apple 3.5 drives with Revision A daisy chain interface boards in the following configurations:
An Apple IIgs with one or more Apple 3.5 drives attached, and one or more UniDisk 5.25 drives daisy-chained to one of the Apple 3.5 drives.
An Apple IIgs with one or more Apple 3.5 drives attached, and a DuoDisk daisy-chained to one of the 3.5 drives.
The spinning problem is the result of electrostatic buildup within the circuitry of the Revision A daisy chain interface board. This problem causes no permanent damage to the drive, and normal functioning returns if the system is powered off and back on.
If an Apple 3.5 drive exhibits the spinning problem while in one of the configurations described above, replace the Revision A daisy chain interface board with a Revision B board.

Tempest

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Dec 9, 2018, 10:34:10 PM12/9/18

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Guess I have a Rev B board then. I have both 5.25 and 3.5 drives hooked up to my IIgs.

loc...@locutus.org

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Feb 9, 2019, 6:24:05 AM2/9/19

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When I had a //e card I was using a clone (half hight) Disk ][ drive on it. It didn't seem to have at problem with it. Then I went to an UniDisk drive 5.25 when I got an Apple 3.5 UniDisk drive with no problems either.

As for the ROM 03 GS I'm not sure on that. I think I started using a Plat 5.25 Drive before I went back to using Apple ][ disk drives.