Unidrive 3.5 issue

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Unidrive 3.5 issue

I recently picked up a unidrive 3.5 of unknown working condition to use with my ROM4 //c. Unfortunately, seems like the condition is not working. When I put a disk in, it makes a sound like it's trying to line up the peg with the hole on the disk hub. Then when I boot it on my IIgs (the //c is currently boxed up), I hear a motor inside spin on-off-on-off-on-off and then the IIgs just gives me the sliding Apple error screen. I should note that I disassembled it before doing anything and cleaned the heads carefully with a qtip and 99% IPA. 

 

The drive itself looks pretty much identical to the non-Unidisk 3.5 drive. I'm assuming I could swap the drives with one of my working 3.5 drives and test both that way? That should at least narrow down the issue to either the drive itself, or the Unidisk daisy chain board, correct?

 

Any early guesses on what could be wrong, and possible fixes?

 

Thanks!

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Same drive mechanism.

Same drive mechanism. Hopefully it's the drive mechanism and not the daisy chain board

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//c Unidrive purpose

Are you trying to get it to work because:

1) You have 3.5 diskettes for which you want to read their data;

2) You want to use 3.5 diskettes to transfer files to your legacy Macintosh; or

3) It is just fun to have one to look at?

I would suggest you get BMOW's Floppy EMU and solve all 3 problems (plus gain a psuedo-hard drive for both your //c and legacy Mac)!

 

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I swapped the mechanism from

I swapped the mechanism from my "dumb" 3.5 drive, and the Unidisk booted with it. So the good news is that the interface in the Unidisk case is good. The bad news is the Unidisk drive mech still wouldn't boot properly when hooked up in the "dumb" case. I cleaned the heads (again) to no avail. Also tried recapping the drive mech as a last ditch attempt, no go.

 

Unless anyone can point me towards some kind of troubleshooting doc or has any ideas on what to try, I guess I'm in the market for a Sony MFD-51W. Or maybe a dumb 3.5 drive on the cheap with a busted up case that I could transplant.

 

As for why I want it, just because. I like the old Apple hardware and like to pick up stuff I couldn't afford as a kid. I already have a Floppy Emu for the past year and half. 

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nick3092 wrote:As for why I
nick3092 wrote:

As for why I want it, just because. I like the old Apple hardware and like to pick up stuff I couldn't afford as a kid. I already have a Floppy Emu for the past year and half.

Same here: I like to be able to play with software that I could not afford at the time I owned my //c and my Mac SE/30, as well!

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nick3092 wrote:I swapped the
nick3092 wrote:

I swapped the mechanism from my "dumb" 3.5 drive, and the Unidisk booted with it. So the good news is that the interface in the Unidisk case is good. The bad news is the Unidisk drive mech still wouldn't boot properly when hooked up in the "dumb" case. I cleaned the heads (again) to no avail. Also tried recapping the drive mech as a last ditch attempt, no go.

 

Unless anyone can point me towards some kind of troubleshooting doc or has any ideas on what to try, I guess I'm in the market for a Sony MFD-51W. Or maybe a dumb 3.5 drive on the cheap with a busted up case that I could transplant.

 

I have found failed logic boards on those drive mechanisms.  I have also sucessfully transplanted one from a dead compact Mac.  If you go that route be careful it's 800K and not a 400K drive.

Apple 3.5" drives are still plentiful, so that is also a valid repair route.  

 

Save the eject mechanism out of your dead drive.  There is an idler gear in those mechanisms that is prone to breakage, so it could come in handy as a spare part.

 

 

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baldrick wrote:nick3092 wrote
baldrick wrote:
nick3092 wrote:

I swapped the mechanism from my "dumb" 3.5 drive, and the Unidisk booted with it. So the good news is that the interface in the Unidisk case is good. The bad news is the Unidisk drive mech still wouldn't boot properly when hooked up in the "dumb" case. I cleaned the heads (again) to no avail. Also tried recapping the drive mech as a last ditch at

 

I would save pretty much everything from even failed drives these days because people will still pay for potentially rebuildable or reworkable parts.

 

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Actually, I somehow managed

Actually, I somehow managed to get the drive working. I took it all down to parts and cleaned everything including the heads for the 3rd or 4th time. Lubed the the eject mechanism, and suddenly it was reading. So I was quite pleased about that.

 

 

Of course the usual gear was stripped out. I also found that this eject gearbox/motor (while almost certainly seappable with the motor) is designed slightly differently. The gear box cover is held on with screws, instead of a spring loaded tab. I also discovered once I got replacement gears, if you tighten those screws too much, the motor can't spin the gears. So I had to bad them out slightly. Now it ejects fine.

 

 

And lastly, I found that back in October, someone published new designs for the gears. These are the "2.0" version, they used microscopy imaging to reproduce the design of the original. I've attached some pics of the gear I got last year (left), original (middle), and 2.0 (right). The teeth do look a little better on the new 2.0. Hard to say how much of a difference it really makes though.

 

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