How to build an external 5.25" floppy drive

As you may have noticed, most new m/b's don't have FDD connectors, so if for some bizarre reason you want to access a pile of old 1.2meg floppies, you're SOL. There is no such thing as an external 5.25" drive. Go ahead, look. They don't exist. The only exception is some funky contraption sold by Apple that requires it's own adapter card.

But since you can still get external 3.5" FDD's that connect via USB, you'd think it would a pretty straight forward swap. You would be wrong.

When you crack open a 3.5" drive, and I do mean crack open since they are welded (sonic welding) shut, you find a weird 26 pin connection going from the USB interface to the drive electronics. And they don't even have the decency to make it a standard pin and socket connection. Oh no, they use a ribbon cable that goes into some sort of pressure connector.

Fortunately, there is an adapter which I assume is made for this purpose. If not, please let me know since this is my plan at the moment. Here's a link and a pic.



The guts of the USB interface terminate in a 26 conductor ribbon cable. But what I can't tell from this pic or any other I've been able to find is if the smaller connector takes a ribbon cable. It looks like it doesn't since it has a socket for accepting pins, but I don't know.

In the worst case though, I have no problem wiping out the soldering iron. What I'm interested in are opinions as to the best way to go about this. thanks.

OK, I need some help here. Below are pix first of the USB interface and then the header on the controller board for the floppy. The ribbon cable on the interface goes into the header. The cable is single row, not double row and the header is the press-in kind but with the addition of a gate that you press down to lock the cable in place.

I can't find any connectors like that online mainly because I don't know what it's called. I've found connectors that are purely press-in, friction type with no locking latch. And even those don't seem to go by any standard name that I've been able to find.

Does anyone know what I should be looking for here?

I think what I need is a connector that has the press-in type connector on one side going to a double row of 26 pins (13 x 13). If I find that, I can plug that into the 26 pin female connector on the adapter shown in my first post.

Thanks.

[Frick]

I don't know what they're called either, but I think i've seen them in older laptops and such.

[PHaS3]

Pretty sure its called a ZIF (Zero Insertion Force) Ribbon or something similar. Not sure where you can get a connector for it though...

Originally Posted by PHaS3

Pretty sure its called a ZIF (Zero Insertion Force) Ribbon or something similar. Not sure where you can get a connector for it though...

As far as I can tell, it looks like they're called FFC/FPC ZIF/LIF connectors. FFC = flat flexible cable. FPC = flexible printed circuit. LIF = low insertion force.

Here is a good pdf that gives you the background behind these cables and connectors - http://www.avx.com/docs/catalogs/ffchist.pdf

I ordered an adapter today which is like the one below, but that one seems to be a better design. Plus it clearly has an FFC connector for the ribbon cable coming off of the USB interface. I think the one I ordered did, but I'm not sure.



FYI, sometimes less is more. I've been searching for several hours total. Finally tonight I decide to just put "floppy adapter" into google and bam, good hits on the first page. I can't believe that I forgot this basic rule of searching yet again.

[whitrzac]

Wouldn't it be cheaper/faster to build a desktop with free/cheap parts and put everything on a USB flash drive?

[digibucc]

Originally Posted by whitrzac

Wouldn't it be cheaper/faster to build a desktop with free/cheap parts and put everything on a USB flash drive?

not really. plus then you'd need to use an old cheap computer.

I've had to go that route for getting stuff off of old Travan 4 and 5 archive tapes. But then I found a way to access the tapes using VMPlayer and accessing an IDE tape controller as a SCSI device in the VM. This was much, much better than having an extra rig lying around.

Plus, as I've been researching this and bouncing around the web, I've found that there are quite a few people who are interested in something like this. So if/when I'm able to build this, I can lay out clear instructions with sources for parts so that anyone can grab a cheap usb 3.5" floppy and for an additonal $30-50, depending on how ghetto they're willing to go (i.e., with or without an external case) can convert that plus a 5.25" floppy into an external, USB based drive.

Well, the vendor (CWC group) sent me the wrong part. It looks like it's an IDE adapter for a CD ROM rather than a floppy adapter. Now I have to hope they don't give me a hard time about sending me the correct part and it will probably be at least another week until I get it. Fuuuuuuuuu......

[Cuzza]

Intriguing. Reminds me of the problems I had with getting my Sega keyboard converted to PS/2, fiddling around with ribbon cables and adapters to floppy cables (see link in sig if interested)

Don't think I'll be much help here but I'll keep an eye on proceedings. Good luck, and by all means break out the soldering iron! More fun that way.

[PVTCaboose1337]

Have fun finding the drivers for this. No motherboard after 1998 will support 5.25" disk drives. At least the operating systems don't. I have personally used a 5.25" disk drive to flash bios, however, Win XP, 2000, 7, don't work with floppies. They will recognize they went in the drive, but will not write or read.

This will be USB based and I've had no problems reading and writing to a USB floppy in W7

[PVTCaboose1337]

A 3.5" floppy? Sure. Drivers are still working for those. For 5.25" I would love to have a working one again, but it seems not to be possible. I need more software for my 5150!

Originally Posted by PVTCaboose1337

A 3.5" floppy? Sure. Drivers are still working for those. For 5.25" I would love to have a working one again, but it seems not to be possible. I need more software for my 5150!

It doesn't matter. The drivers are for the USB device not the floppy. Low-level addressability should be handled by the onboard electronics, not the host OS.

[Cuzza]

That's what I thought. But then what makes you sure the USB interface will talk to the 5.25" drive?

Originally Posted by Cuzza

That's what I thought. But then what makes you sure the USB interface will talk to the 5.25" drive?

It should be able to talk to any device that uses the same protocols. For example, I hooked up an IDE tape drive to a USB interface made for an IDE HDD and it worked fine since it was also an IDE device.

The 5.25" uses the same protocols as the 3.5". If anything, it is probably a subset since the 5.25" was a much earlier version of the same kind of device. It's also the exact same cable - once I convert it from 26 pin to 34 pin. But that's not an issue either if you look at the pin-out diagrams - http://www.martinruss.com/sy99adapter.html

Now if I were trying to hook a floppy up to a USB interface for an IDE drive, that would be something else entirely.

[Cuzza]

oh sweet. You have been digging up some obscure web pages!

Thanks. There's not a lot of stuff out there anymore on 5.25 floppies. Which makes sense since they were being phased out when the internet was still a baby. Although anything on 3.5" would also apply to 5.25 as far as pin-outs.

Anyway, I got the new part yesterday. CWC Group was very prompt about resolving the issue and got the new part out to me in a couple of days. For anyone who wants to try this at home, the part you want is the Intel 26 Pin to 34 Pin Converter, P/N: C74972-202

This will re-route the pins from the 26 conductor connector to the proper pins on the 34 pin connector. It also provides an power source since the 26 conductor connection has a 5v line built-in but the 34 pin does not.

edit: I think the power connector also provides the grounding point for the 34 pin connector.

After getting the wrong part twice from one vendor, I decided to get a somewhat different solution from another - Alan Computech



I liked the other converter better since it rewired the pins in the PCB. This one does it the old fashioned way of re-routing the individuals strands of the ribbon cable. But whatever. Same thing really.

My problem now is the fact that the drive I have to test with requires a card-edge or slot connector. Those are seriously old school and trying to find anything exotic is basically impossible. I'm trying to think of a work around for that. I have old cables with that type of connector but then the problem is mating one to the assembly above. IDK. I'm going to have to give this some thought. Suggestions are always appreciated.

[comtech]

Have appreciated reading threads below. I have Teac FD-55GFR 5.25" Floppy Drive 1.2M which I am trying to connect to laptop in some way. It seems to have a 'ribbon thread' connector, maybe similar to the below; I count 17 copper strips in this connector, so if it is assumed that both sides need to be counted (17 x 2 = 34), this may be the 34 pin ribbon connector discussed below. Photos are attached.

Has anyone found a way, or know of a way, to get this 5.25" floppy connected to a laptop with USB or 25 pin connector?

Comtech

[qubit]

Originally Posted by twilyth

There is no such thing as an external 5.25" drive. Go ahead, look. They don't exist.

Maybe not now, but to be pedantic they certainly did: I had one in 1985. It was housed in a beige case and had a 12v/5v power connector and the ribbon cable going to it. Zippy thing it was, too. I had it connected to a BBC Master 128 (that's 128 kilobytes, lol).

I wrote a floppy duplicator program on that computer that used all the RAM. It took six swaps to do it!

[bmaverick]

It's been like four years, but I had once seen a 3.5+5.25 external floppy USB drive in the retail chains for a short time. Just can't remember the brand or who made it. This way, you would only need one USB and the drive can read/write to either floppy.

[ValuedClient]

I've followed your work and think you really got a great idea. I joined this forum just to ask a question. Do you have yours working? Thanks and keep thinking outside the box.

It's still on the back burner I'm afraid. I keep putting it off because I can't think of any other solution that soldering leads from the ribbon cable directly to card edge connector.

[lparsons]

Originally Posted by twilyth

It's still on the back burner I'm afraid. I keep putting it off because I can't think of any other solution that soldering leads from the ribbon cable directly to card edge connector.

I was directed to this thread from a discussion elsewhere, and thought I'd add in my thoughts as I am trying for something similar. I thank you in advance for the work you've already done towards this.

First off, I may have an edge -> 34pin MFM adapter. They were fairly common back in the day and might not be terribly hard to find if you poke around a bit. I think there was a time when they were given away at no cost with motherboards.

Second, have you looked at the TEAC (there were probably other vendors as well) combo drives? 5.25 and 3.5 in the same drive; by my understanding they used only one cable connector which was the same as a 3.5 floppy drive; they essentially had internal circuitry to connect the two drives to each other. I'm in the process of picking one up and will start my project with it. Apparently you can jumper them to put either the 5.25 or 3.5 inch drive as the first drive.

Third, do you remember the manufacturer of the USB floppy that you dissected? I figure older drives are better donors for parts for this, and am just starting to look for a drive for that purpose. I happen to have a USB CDROM enclosure, so I have the power requirement met through that. I just need the important bits to adapt the floppy to USB.

thanks again!