Modifying PC Floppy Drive for Amiga Use

BLTCON0

Math inside
AmiBayer
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Sorry to hijack, but can you provide a pointer to the modification you performed? I tried to convert three such Samsungs a few months ago following some info in an EAB thread and, while it worked, the drives kept re-reading everything 2-3 times before moving on, leading to excess noise and slower performance. Strange thing is a couple of games with custom loaders apparently worked fine. I'm wildly curious.
Thanks!
 
OK DyLucke, payment received (y)
Remember to PM me your home address, then I can ship it.

@BLTCON0:

For sure mate, here's the modification I did:

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What you need:

A welder,
A small cable (4-5 cm lenght)
A tweezer

Translation of the instructions:
Picture 1: Move the DS0/DS1 jumper from DS1 to DS0;
Picture 2: Solder and end of a small cable on ribbon connector's pin 2;
Picture 3: Move the DC resistor to RDY helping you with the tweezer, then solder the other end of the cable on DC (just as seen in the picture). So now you bridged DC with the pin 2 of the ribbon connector.

(Pictures are from Matteo90's tutorial on AmigaNews.it - http://amiga.ikirsector.it/forum/viewtopic.php?f=38&t=14330)

I modified all the drives using an hot air soldering station.
Here's a video showing how the drive works on my A1200 (y) - http://www.youtube.com/watch?v=2J4yzpCReyg
 
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Is great guide, and mod looks well done.

Why not short the hd switch to always dd? So no tape is needed?
 
@Enzo45s
Thanks mate, great stuff and very well done mod! (y)

I still have one of those SFD-321B's, it's marked /EZ rev S2, I'll have another look at it according to your guide. Looks different from yours though.

I second jvdbossc's suggestion too (as long as the diskchange signal doesn't get killed along).
 
Mod done and works a treat! My SFD-321B is indeed different, but all points of interest were there.
As for the always-DD fix, my model uses the 'active open' type switch so it can't be shorted.

No disk: 1-3 & 2-3 shorted
HD disk: 1-3 shorted
DD disk: (none shorted)

but obviously it's easily converted to always-DD by just desoldering the high-density switch.
This doesn't harm the diskchange signal (apparently it's controlled by the other switch).
And we get a spare switch to replace the other one should it ever fail ;)
 

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I have split these posts from this for sale thread and placed them into a new thread on how to modify an existing brand of PC floppy Disk Drive.
 
Alps df354h (148f)

Alps df354h (148f)

Here's another type of PC floppy drive modified for Amiga use - this time an ALPS DF354H (Revision 148F, but I don't think the revision matters - I've done this to a 121G too.)

Image attached, labelled as follows: (Feel free to cringe at my dodgy soldering!)

A: Use desoldering braid to remove solder from DS1 pads, bridge DS0 pads with solder. (Cause the drive to appear as unit 0, as expected by the Amiga.)

B: Cut trace leading from pin 2 of socket to chip. (Disconnect the redundant HD signal)

C: Cut trace leading from pin 34 of socket to chip pin 5. (This is the diskchange signal, which we re-route to pin 2 in step E.)

D: Solder a wire from pin 34 of the socket to pad marked "RD". (Makes the Disk Ready signal available to the Amiga)

E: Solder a wire from pin 2 of the socket to pin 5 of the chip. (Re-routing the diskchange signal.)

F: Solder a wire from the pad marked HD2 to the pad at the top left which happens to be a convenient ground. (Bypasses the HD detect switch so all disks are treated as DD - thus no need for tape over the HD holes.)

Hope someone finds that useful. :)
 

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@Zetr0: Well done! Thanks (y)

@BLTCON0: I removed the HD switch from one of my drives and it works very well! Thanks again for the advice mate (y)

@robinsonb5: That's interesting, I surely have some Alps Electric drives so I'll try to do it, thanks! ;)

Does anybody know if there is a PC floppy drive modifiable for Amiga use but as an HD (1,68mb) drive? That would be veeeeery interesting :p
 
@robinsonb5
Nice one on the HD detection disabling! I modded an Alps too a few months ago but IIRC it wasn't easy reaching the actual switches. Time to revisit.

@Enzo45s
There seems to be a specific SONY model (MP-920 something?) as well as a TEAC one (which I presume is a clone of the SONY, or vice versa) which can be modded, but modding in this case implies extra logic being added to the drive, not just rewirings. I think it was an EAB thread.

Speaking of which, does anyone know the ID for Amiga high density drives through the MTRxSEL + RDY procedure? My copy of the hardware manual is from the pre-HD era :)
 
@robinsonb5
Nice one on the HD detection disabling! I modded an Alps too a few months ago but IIRC it wasn't easy reaching the actual switches. Time to revisit.

No, I think reaching the switches themselves would have required desoldering the ribbon cable that leads to them. Way too much like hard work!

Seeing the EAB Sony thread reminds me that the top cover of the Alps drives will foul the casing on an A600/A1200 - I simply unclipped it, and slid it backwards a quarter of an inch - the sides grip firmly enough that it'll stay put.

For the drive button, since I'm none too confident with this stuff yet (and since PC floppy drives are, it seems, easier to come by than genuine Amiga floppy buttons!) I went the Polymorph-and-Araldite route.
 
@jvdbossc
Yes that's the thread I seemed to recall. So, have you converted them into "genuine" Amiga HD floppy drives? Or you're talking about the standard DD "just rewiring" mod as (extensively) pictured in that thread?
 
@jvdbossc
Yes that's the thread I seemed to recall. So, have you converted them into "genuine" Amiga HD floppy drives? Or you're talking about the standard DD "just rewiring" mod as (extensively) pictured in that thread?

Just dd drives, I do not care much about HD, since most amigas use DD. The thread about HD seems dead end.
 
I have done this 2 years ago on an ALPS and works great. I have an external drive on my miggy with a Chinon FG-357 and it works too. When I tryied to replace it other drives didn't work. I also used an internal A500 with jumper DS0 and DS1 but no luck.
 
Here's another type of PC floppy drive modified for Amiga use - this time an ALPS DF354H (Revision 148F, but I don't think the revision matters - I've done this to a 121G too.)

Image attached, labelled as follows: (Feel free to cringe at my dodgy soldering!)

A: Use desoldering braid to remove solder from DS1 pads, bridge DS0 pads with solder. (Cause the drive to appear as unit 0, as expected by the Amiga.)

B: Cut trace leading from pin 2 of socket to chip. (Disconnect the redundant HD signal)

C: Cut trace leading from pin 34 of socket to chip pin 5. (This is the diskchange signal, which we re-route to pin 2 in step E.)

D: Solder a wire from pin 34 of the socket to pad marked "RD". (Makes the Disk Ready signal available to the Amiga)

E: Solder a wire from pin 2 of the socket to pin 5 of the chip. (Re-routing the diskchange signal.)

F: Solder a wire from the pad marked HD2 to the pad at the top left which happens to be a convenient ground. (Bypasses the HD detect switch so all disks are treated as DD - thus no need for tape over the HD holes.)

Hope someone finds that useful. :)
You sir are an absolute legend!! I was given a 1200 with faulty drive and started looking at options. Was at work there is an old IBM PC on the shelf waiting to be thrown out. Ripped the drive out and started poking around. Couldn't find anything that resembled the RY points etc. Only the DS points.
Then started poking around with google and found this thread. (y) Diagram has been saved now and will be applied this evening when I get home!
Lets see how we go.
 
I have a Commodore 1581 3.5" drive which also is designed to use Amiga floppy drives so this mod also works with them. (I did it back in 2006.) But now I have another faulty 1581 drive and the NOS PC Floppy drive I have (Mitsumi D359M3D) doesn't seem to have a DS0/DS1 jumper anywhere.

Is there a workaround?
 
I remember reading that people have been able to make defunct Chinon mechanisms working by changing the capacitors on the drive mechanism PCB.
 
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