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Using 3.5" FDDs as external drives possible?

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ardsleytank

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So I have a TRS-80 Model III, and I had a thought while looking at the card edges on the bottom. Is it possible to make an external Floppy drive enclosure using 3.5" drives?

It would help, since 3.5" floppys are readily available. And it would look cool. :cool:

Thanks,
Peter

(P.S. What's the right word for plural floppy disks? Floppys? Floppies?)
 
"Floppies", following the usual rule for y-ending nouns not preceded by a vowel.

I don't see a reason why this couldn't be done. The floppy/diskette interface is the same between 5.25" and 3.5" drives, by and large.
 
I've been wanting to get a 'simple' USB floppy controller for quite some time.

My research has shown that some of the earliest USB floppy drives were internal drives with a USB controller, but I've never actually seen one.


The closest things we have today that I know of are read-only multi-format archiving controllers such as the Catweasel and Kryoflux. The FC5025 runs 5.25" drives, but it too is read-only.
 
Okay, so the trick is, my 3.5" drives don't have jumpers. But one I did find had three holes in the PCB next to the Power plug.

On the left hole, it was marked "0". The right one is marked "1" and the middle one "DX". They're just holes, not pegs. Are these where the jumpers go?
 
ardsleytank said:
Okay, so the trick is, my 3.5" drives don't have jumpers. But one I did find had three holes in the PCB next to the Power plug.

On the left hole, it was marked "0". The right one is marked "1" and the middle one "DX". They're just holes, not pegs. Are these where the jumpers go?
Click to expand...

Should be. That might be a problem though. If your Model III has the traditional 2 internal drives, you will need to set the external drives to DS 2 and 3 which that drive can't do.
 
I have a pair of external 3.5" floppies powered by 5v that work on the Model IV.

On the M4 controller card's bottom edge connector, it appears that DS 0/1 are already wired as DS 2/3, so they work fine as-is (they're set up as 0/1). On the M3 controller it may be different, but even if it is, it's pretty easy to rewire them (on the cable). No need to try to find DS3/4 on the drives themselves, if it is not already supported.

You do need DSDD drives at the maximum though. 1.44MB HD PC type drives are not likely to work.

Someone will be along soon to correct any errors in this! :)

Cheers
JonB
 
ardsleytank said:
Okay, so the trick is, my 3.5" drives don't have jumpers. But one I did find had three holes in the PCB next to the Power plug.

On the left hole, it was marked "0". The right one is marked "1" and the middle one "DX". They're just holes, not pegs. Are these where the jumpers go?
Click to expand...

You can also juggle the drive selects at the connector. DS0-3 most often are just pads with jumpers leading to a main drive select.
 
Fire-Flare said:
I've been wanting to get a 'simple' USB floppy controller for quite some time.

My research has shown that some of the earliest USB floppy drives were internal drives with a USB controller, but I've never actually seen one.


The closest things we have today that I know of are read-only multi-format archiving controllers such as the Catweasel and Kryoflux. The FC5025 runs 5.25" drives, but it too is read-only.
Click to expand...

SMC (now SMSC) early on offered a USB-to-legacy floppy interface chip. I probably still have the datasheet.
 
Easy to do. I have 3.5" drives in my Model 4. Also an external SCSI enclosure which has 2 3.5 drives in it and use the power supply built into it. Just put the drives into a 3.5" frame. Some of the card edge to pin headers adapters for the 3.5 drives have a jumper block where you can select which drive is 0 or 1.
 
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