Getting a DuoDisk unit working again...

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Getting a DuoDisk unit working again...

I came into posession of an Apple IIe with a DuoDisk unit.  It sat for years in a barn and is caked with mud dauber nests on the inside.  As I'm cleaning it out, I've torn down one of the two DuoDisk drives and I want to establsih two things:

 

1.  Whether or not I need to do the DuoDisk mod to the analog board

2.  How to test the stepper motor before putting everything back together.

 

On the first point, I can't establish whether or not the analog board is one of the three that require the mod for preventing disk overwrites.  That is, there is no 676-[]101, 676-[]102, or 676-[]107 marking.  On the back, I see 820-0123, but as I look at schematics, I get the impression that's not the number I'm really looking for...  But I see no other numbers on the PCB like that.

 

On the second point, I've found descriptions of the 20-pin connector, but they are for Disk II or DuoDisks that appear to be different than mine.  The article on Wikipedia describes wire colors which I really couldn't correlate to the connector I have.

 

Any tips or a cache of technical documents I've not yet found?

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Apple duodisk ?

Hi Joel,

It seems you don't have an Apple Duodisk like this one. If it's true, you probably don't need the mod.

Pictures of the case and the analog board would be very welcome to verify.

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Number ......

The Analog board is the one inside Drive 1 in the Duodisk. 

You may have to unplug the cable near the back right of the board to see the board's model number. 

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amauget wrote:

[quote=amauget]

Hi Joel,

It seems you don't have an Apple Duodisk like this one. If it's true, you probably don't need the mod.

Pictures of the case and the analog board would be very welcome to verify.

[/quote]

 

Yeah, it sounds like maybe he has two UniDisk or Apple 5.25" drives.  Those are similar to a Duodisk, but not the same boards in them.

 

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It's a DuoDisk unit.  The

It's a DuoDisk unit.  The board number was hidden well, so it wasn't until I unplugged a few harnesses that I finally saw it.  It's a 676-[][]102...

 

I think that means a resistor needs to get clipped somewhere...

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joel_graff wrote:

[quote=joel_graff]

It's a DuoDisk unit.  The board number was hidden well, so it wasn't until I unplugged a few harnesses that I finally saw it.  It's a 676-[][]102...

 

I think that means a resistor needs to get clipped somewhere...

[/quote]

 

Google provides this wisdom from Dr. Steven Buggie:

 

https://stason.org/TULARC/pc/apple2/faq/09-006-What-DuoDisk-mods-are-necessary.html

 

 

 

 

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Actually I mis-credited that.

Actually I mis-credited that.  The article was by Jeff Hurlburt, Dr. Buggie posted the last comment to it.

 

 

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The mods are only for hooking

The mods are only for hooking to a IIgs and not a IIe. There should be nothing needed for the IIe.

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rittwage wrote:

[quote=rittwage]

The mods are only for hooking to a IIgs and not a IIe. There should be nothing needed for the IIe.

[/quote]

 

Well, the second one.

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rittwage wrote:[quote
rittwage wrote:

[quote=rittwage]

The mods are only for hooking to a IIgs and not a IIe. There should be nothing needed for the IIe.

[/quote]

 

Well, the second one.

 

Just to be clear, although the mod is required for using the DuoDisk as the last two 5.25 drives after the two 3.5" drives with the IIgs' SmartPort, the modification does not affect the DuoDisk's behavior when used with earlier Apple II's and the Apple 5.25 Disk Controllers.

 

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What do you hope to

What do you hope to accomplish with "testing the stepper motor"? Is there a reason why you suspect a problem?

You shouldn't be touching the head or the stepper motor, leave them untouched. It will either work or won't and again, don't be touching it or the head because that could cause damage you may not be able to correct.

I think you best first step would be powering it up and checking for the spindle motor spin and head calibration. While opened up can also put a strobe on the speed markings with drive door open.

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jeff d wrote:What do you hope
jeff d wrote:

What do you hope to accomplish with "testing the stepper motor"? Is there a reason why you suspect a problem?

You shouldn't be touching the head or the stepper motor, leave them untouched. It will either work or won't and again, don't be touching it or the head because that could cause damage you may not be able to correct.

 

I am leaning in that direction also.  Either the stepper motor works or it doesn't

I would spend as much time as is necessary to remove any trace of insect activitiy, clean it well, put a tiny drop of light machine oil on the spindle motor shaft, lube the sliders with the smallest amount possible of the lightest machine oil you can find (I like LPS-1), clean the read/write head with a cotton swab soaked in isopropyl alcohol or "Ronsonol" ("zippo" lighter fluid) and then boot the computer with the cover off the Duodisk and check to make sure that at least drive 1 moves around as expected.

 

If there are issues, you can then address them in turn.

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