IBM/Teac external floppy - modding possible?

Hi guys, first post, I'm new here

Thing is, I found this old external IBM Thinkpad floppydrive at work, and wondered if it would be possible to modify the drive and the connector to work as an external drive for my Amiga600.
Anyone know if it would be possible? I've seen a lot of guides on modding internal PC drives for the Amiga.

It is an old external Teac FD-05SLHG drive (IBM P/N: 05K8804) in an external IBM floppy case P/N: 05K6187.

[Jope]

You might be able to get it to work as DD. You'll probably have to dismantle the mechanism from inside the module and then work from there to figure out which wire is which on the cable.

I can't be bothered to google the P/Ns up for you, but that drive looks like it was used with the ThinkPad 600 series of machines. Perhaps you can find the laptop side pinout somewhere.

And naturally you'll need to build the external drive motor flip flop / ready pulse circuit that is expected of an external Amiga drive.

[demolition]

Originally Posted by Jope

And naturally you'll need to build the external drive motor flip flop / ready pulse circuit that is expected of an external Amiga drive.

I think it should be possible to fit those few digital ICs inside the d-sub housing. I'm guessing that there's no active electronics in that box so the cable contains all the standard floppy signals. In that case, it should be possible to perform the mod as long as there is a RDY signal to be found somewhere on the drive.

[mark_k]

I'm not sure about your specific drive, but there were other types of IBM external floppy which you might have more luck with, possibly even as a high density drive too.

Back in the day Amitek sold a Dell DX9 external floppy drive (with Amitek badge covering the Dell logo ), along with a connecting cable. That worked as a normal/proper HD floppy drive with Amigas; it spins at 150rpm with HD disks. I have one.

You can see pictures of the drive and cable (not mine) on this Amibay thread. I'm not sure what circuitry is in the cable, but it doesn't look like they modified the drive at all (though I guess that is possible).

Now, the Dell DX9 drive is apparently made by Teac and is functionally identical to certain drives IBM sold for use with Thinkpad laptops. See this page about that. If you Google the various IBM part numbers on that page, you'll see pics of the IBM version, which though the casing differs seems to use an identical connector. There are pictures of what is probably the IBM version of the drive in this eBay listing.

So it would be nice to know:
- Exactly what circuitry is in the Amitek cable?
- Did Amitek modify the DX9 drive at all?

If they didn't modify the drives, it might be feasible to make your own cable.

[pandy71]

Originally Posted by mark_k

That worked as a normal/proper HD floppy drive with Amigas; it spins at 150rpm with HD disks. I have one.

Before Intel 82077, uPD765 was used on PC and when IBM introduced PS/2 family there was speed limit for 765 (500kbps), IBM introduced with PS/2 1.44/2.88MB floppies and to support 2.88MB on 500kbps they use same principle as Amiga HD - they spin floppy with half RPM. With 82077 where faster transfer speed was introduced this was no longer required - perhaps http://download.intel.com/design/arc...s/29209302.pdf this can help (some drives listed in this app have PS/2 mode that can suggest they spin with half RPM when compared to normal AT mode).
Half RPM FDD's was used only in small number of PS2 desktops + some notebooks (but in notebooks for longer thus there is higher chance to find such FDD in IBM notebooks).

Problem with this half RPM is that all FDD electronics remains in 500kbps mode so it may give suboptimal results from Amiga perspective (some disk can be consider as corrupted where Amiga FDD can read them correctly).

http://www.os2museum.com/wp/?p=472

Seems that this cover whole story (however seem that half RPM are unknown for author).

[ElectroBlaster]

I have one of these Dell DX9 drives sold by Amitek!

The cable, imho was badly put together which resulted in mine falling to bits

I still have everything so if I can fish out soonish, I will take some pictures of it.
From memory, there is a standard 23pin moulded end for the Amiga, terminating to a custom made board with the 23pin cable wires soldered onto pads. The board carries an IC chip and a few extra resistors etc.

When the cable broke! Some of the wires ripped off this board and I had no common reference to try and sort it out. So it has been useless for many years. When it worked! It did its job well, no software or drivers were required! it just worked as it should

EDIT: I am going to make this my mission! I realise now, if Amitek used an off the shelf GAL chip... then its obvious there has to be some kind of pinout schematic for it! Then maybe with luck somebody can trace all the lines and figure out where some of the wires go. I seem to recall at least 5 to 8 wires came adrift on one side... I would be stoked to get it all sorted and working again

[jbenam]

Originally Posted by ElectroBlaster

EDIT: I am going to make this my mission! I realise now, if Amitek used an off the shelf GAL chip...

As far as I know, GAL are sold as empty and are then programmed with some code in them That means Amitek had programmed a small piece of code which helped them interface the drive with the Amiga with no additional software

tl;dr You need to have the original GAL to make this work, or if the code was simple enough, someone should rewrite it from scratch

[prowler]

@mark_k and ElectroBlaster:

I have an Amitek external floppy drive and connecting cable that works as a High Density floppy drive with Amigas, which spins at 150rpm with HD disks and needs no special drivers, but requires WB3.x IIRC.

I have never used it, so I have no idea whether it works. It appears to be intact, but is rather grubby.

First, I will clean it up a bit and post some pictures, and I'll investigate further if you are curious.

[ElectroBlaster]

Excellent guys

Exactly what I meant regarding this Amitek I have! Nothing else is needed for it to work other than the cable and the drive. It automatically spins at 150rpm.

When mine worked, it worked great! I also have a pair of Power Comuting XL drives and the only way to get HD formatted disks is by using a software patch, the amitek needs nothing to run afaik. Maybe the chip inside the lead has all this sorted out?

I just need to hunt those two bits down. I have the actual drive here right now... might take a day or two to find the lead now...

[mark_k]

Originally Posted by prowler

I have an Amitek external floppy drive and connecting cable that works as a High Density floppy drive with Amigas, which spins at 150rpm with HD disks and needs no special drivers, but requires WB3.x IIRC.

I have never used it, so I have no idea whether it works. It appears to be intact, but is rather grubby.

First, I will clean it up a bit and post some pictures, and I'll investigate further if you are curious.

Yes please. I'd like to see exactly what components are in the connector/cable. If I remember rightly, my one looks to have been sealed with hot-melt glue. I don't want to take apart my cable because it may well not work again afterwards. Though, maybe you'll feel the same about yours!

if it turns out that the components are standard/easy-to-find, and the drive itself wasn't modified, one of those old ThinkPad drives could be a cheap option for getting a real Amiga HD floppy drive. The IBM drive comes with a cable (or at least, it should) with proper connector on the drive end, unlike the Amitek cable which just has a PCB thick enough to plug into the drive connector. So maybe it would be possible to cut off the laptop end connector and fit a 23-way D, with the required components inside that connector.

[ElectroBlaster]

Originally Posted by mark_k

If I remember rightly, my one looks to have been sealed with hot-melt glue.

100% Correct! Mine was the same. This p*** poor way they sealed it was the main cause of mine turning into a useless pile of c...!
The connector began to drift apart and the glue was loosing its bonding strength. One day I decided to move it and then, well that was that! It just gave out and came apart

Originally Posted by mark_k

I don't want to take apart my cable because it may well not work again afterwards. Though, maybe you'll feel the same about yours!

I would recommend you do not even attempt to take yours apart! The wires are embedded in the hot glue . It is no loss at my end m8! mine is already in bits. So in a way I have kinda done people a favour if it can be reversed engineered in some way!

Originally Posted by mark_k

So maybe it would be possible to cut off the laptop end connector and fit a 23-way D, with the required components inside that connector.

It is a complete mystery as to why they did not do this in the first place? The correct cable for the drive, with a soldered on 23pin connector and the gubbins inside the 23pin plastic shroud. I am sure the board on this connector is nothing more than an ic chip and maybe 1 or 2 tiny components. Just have to find it now... I have a pretty good idea where it is infact, just have to get in the storage shed and move some boxes

[ElectroBlaster]

Also to add! Because my cable is fubard... I may aswell go ahead and open the drive as well... find out exactly what drive mech they used on these dell's.

They were used on Dell notebooks afaik? Mine was second-hand and was treated as a curious oddity by whoever I bought it from. Also Dell had covered the plastic in this nasty horrible rubber stuff and I sat there and picked all of it off... made it look much better lol. Then after all that I only used it a couple times before the cable went

EDIT: Something of interest here http://www.facstaff.bucknell.edu/findeis/flopinfo.html

EDIT2: I am running ahead of myself here but the possibilities look good! These drive mechs appear to use "ZIF" ribbon connectors. Now if you can find a ZIF to 34pin convertor, then along with a custom board and a reversed engineered chip... Well I can see having two of the drives shoehorned into an Amiga 1200, both giving the ability to format HD1.77mb disks or even formatting 1.44mb pc disks. I have seen a mod somewhere, an a1200 with two of these drives already mounted... forget which forum though, either this one or Amibay.

[prowler]

Okay, here are the (VGA res) pics I took of my Amitek external Amiga HD floppy drive this evening.

The enclosure has some oily stains on it, and will probably need to be immersed in a detergent solution to remove them when one of us has figured out how to get it apart.

I have no fear of taking the cable apart. The hot glue is fairly soft and can probably be prised away with a bit of care.

The felt pads underneath were, I assume, added by a previous owner, as the original lower left one in picture 2 is missing.

If I can dismantle the drive enclosure and cable, then I will take some higher res pictures and trace out the circuit.

[ElectroBlaster]

Originally Posted by prowler

If I can dismantle the drive enclosure and cable, then I will take some higher res pictures and trace out the circuit.

If you do decide to open the cable that would be brilliant! working out what wire goes to each pad on the custom board would not only mean I can finally fix my drive, but also means the whole lot can be cloned with a bit of luck. this will be an interesting little hack

[prowler]

Hey, I've just managed to prise open the drive enclosure and remove the top!

The drive mechanism is secured to the base with a single screw inside at the back, which also grounds the chassis to the interface socket.

The first picture shows the opened enclosure. The top is on the right. There is one lug in the centre at the back and three on either side, which need to be pressed inwards through the slots running around the back and sides before the case can be pulled apart. The eject button just lifts away with the top and can easily be reinserted when the drive is reassembled.

The drive mechanism is a Teac FD-05HF.

Well, I'll certainly be opening the cable now.

[ElectroBlaster]

Originally Posted by prowler

Hey, I've just managed to prise open the drive enclosure and remove the top!

The drive mechanism is secured to the base with a single screw inside at the back. (More pics coming soon...)

Well, I'll certainly be opening the cable now.

Excellent stuff! Looks like the drive units are still available to buy

Mine is staring me in the face, well the drive anyway lol. I was going to do mine tomorrow as we have 6hours off. Heading into the shed tomorrow n all.

Also I found this over at Amibay that might be interesting, regarding the conversion of a floppy drive over to the amiga. The adaptor board on it looks interesting as it adapts ZIF ribbon over to 34pin IDC... Been trying to find one on ebay with no luck so far:

Part 3. (August 2014) Converting the PC Floppy and Media Card RW Combo Drive. http://www.amibay.com/showthread.php...-Tower-Project

[prowler]

I've managed to prise off one half of the cable shroud.

Sorry about the picture quality for now. It will improve when the details are more important.

[ElectroBlaster]

Originally Posted by prowler

I've managed to prise off one half of the cable shroud.

Sorry about the picture quality for now. It will improve when the details are more important.

From what I can see! Yours was better than mine, mine was embedded in hot glue!

Thanks for doing these pictures, everything we do will help others including the o/p!

[prowler]

Okay, I now have the circuit board assembly and cable completely out of the shroud.

There are no broken wires, as far as I can tell, but there are three wires (white, green/black and blue/black) which are not connected.

The chip is a PALC22V10-25PC, which is a GAL, if I'm not mistaken.

The component side shown here aligns with the top of the drive. The legend 'TOP' has helpfully been scratched into the top surface of the shroud, either at the time of manufacture or by a previous owner of the disk drive, for it is quite possible to insert the edge connector into the disk drive socket upside down.

The next step will be to get rid of the hot glue and trace the circuit (daylight required!).

[ElectroBlaster]

Originally Posted by prowler

Okay, I now have the circuit board assembly and cable completely out of the shroud.

There are no broken wires, as far as I can tell, but there are three wires (white, green/black and blue/black) which are not connected.

The chip is a PALC22V10-25PC, which is a GAL, if I'm not mistaken.

The next step will be to get rid of the hot glue and trace the circuit (daylight required!).

Wow! this is amazing! My memory actually works a bit... I was right, the chip is a GAL as you have said, but is this beast locked/protected? It will rock big time if its open and readable

I have vague memories of this chip years ago, I even tried to jott down the wires but lost the paper

I was not pleased after it broke and just could not even look at it! It got stashed away only surfacing recently. I am so glad that you have looked at yours! It is something I shouldve done a VERY long time ago tbh.