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?
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.
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.
[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.
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=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
Actually I mis-credited that. The article was by Jeff Hurlburt, Dr. Buggie posted the last comment to it.
The mods are only for hooking to a IIgs and not a IIe. There should be nothing needed for the IIe.
[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.