Modifying PC floppy drives for Amiga use

[Jope]

Originally Posted by RiP

A question: why does X-Copy format disk 2x faster than workbench?

This one would have been better asked in a thread such as http://eab.abime.net/showthread.php?t=69214

But anyway, X-Copy does not multitask, nor does it go through the levels of abstraction that WB Format does. Hence it can write / read the tracks as fast as the drive is capable of moving the data.

[demolition]

Originally Posted by Jope

Are you sure you're not thinking about 5.25" DD and HD drives here? There the DD drives were often 40 track with a wider track width..

However 3.5" DD and HD drives are all 80 track, so the track width/density is the same.

Yes sorry, that was exactly what I was thinking.

[Jope]

Ooh, I did a new one. Sony MPF-520E E/133

Picture here

• You can use the jumper on the top of the PCB to select DS0 or DS1
• Cut the trace between the test point and pin 34, see red line.
• Desolder the solder blob at SH5 to reveal two jumper pads.
• Solder a wire from the test point that used to be connected to pin 34 to the left side of SH5, which is connected to pin 2.
• Solder a wire from pin 34 to a test point near the white flexi ribbon for the ready signal.
• Optionally bridge the HD detect switch near the diskette opening.

[katarakt]

Has it real ready ?

[Jope]

Real enough for me. Stays high when drive is idle, drops low once the drive starts spinning, doesn't cause ghost drives in WB, coexists with a DF1. My test setup is an A500 with one external drive connected, I try WB + Sanity's Arte.

I also did a few more:
http://jope.fi/drives/mpf520-1/
http://jope.fi/drives/mpf920-ealt/

While I was interested in this subject, I added a few that had been contributed via email ages ago:
http://jope.fi/drives/ju257-203p/
http://jope.fi/drives/sfd321b-ke/

[katarakt]

Interesting, i've modified a sfd321b /KE but haven't the 0ohm resistor down below c15 so i soldered dischange directly to the right pad of it.

Ok good. With keirf systest you can check if it's a real ready or not. If it shows oscillating signal it's not a real ready. But besides of that, if everything is working it doesn't matter realy if it's real ready or not.

[RiP]

Possible to replace the upper head of Chinon FB-354 with another brand?

[Jope]

Originally Posted by katarakt

Interesting, i've modified a sfd321b /KE but haven't the 0ohm resistor down below c15 so i soldered dischange directly to the right pad of it.

Ok good. With keirf systest you can check if it's a real ready or not. If it shows oscillating signal it's not a real ready. But besides of that, if everything is working it doesn't matter realy if it's real ready or not.

Aah ok, the ones with other peoples' names in them are not verified by me. :-)

I think I have some Samsung drives in my stash, I'll check the instructions if I find a compatible unit.

I'll stop being a lazy bum and use a scope instead of a dmm to find the ready source in my future mods. :-)

[katarakt]

Great. I don't have a scope and don't know how to use it, but a friend of mine has a scope. If you can make a picture of how the ready signal should look like on a scope, i can ask him to check a special old sony drive for the ready signal

[Marty_McFly]

Hi guys,
I bought 2 brand new PC floppy drives at a very cheap price, they are 2 x ALPS DF354H (rev. 121G) I am attempting to convert one of them to work with my Amiga 500 but although all the welds and connections (including cutting of tracks) it works only as "standalone drive". If other drives are connected simultaneously they start giving errors.
I mean that If I try to use it as df1 (external drive) the df0 unit (a Mitsumi) stops working fine and it does not recognize any more floppies.
The same if I use the modified ALPS as df0. All the external drives do not recognize floppies or are ignored.
What only works is the ALPS drive.

Can you confirm that this floppy drive gives all these problems and is not suitable for a full compatible use with AMIGA?
Thank you for any replies or tips.

[katarakt]

I've modded an Alps DF354H090F, it reacts and looks like a real ready signal, even in kerf systest, but it is not ! ...i think your drive is similar and has not a real ready signal. The main problems appear if you're going to use more than one drive. Best test, except keirf systest, is to test with external drives and format with workbench and try to read the disk after format in workbench shell. Last test with xcopy, but the other ones are more important.

[Marty_McFly]

Hi guys,
This is just to update all the owners of an ALPS floppy drive like mine that the final (and fully working) mod for ALPS drive has been released on the Italian Amiga forum - www.amigapage.it


A huge thank you to the user Sukkopera that found out the way to solve the RDY signal problem once for all.
The trick involves the use of a simple diode in the middle of a jumper between pin 34 and 10 of the drive connector.


More details at the topic below. From page 10 onwards the definitive mods by users liviux76 and Loom4ever:



http://amigapage.it/index.php?op=v&p...012-8-2&page=0

[SukkoPera]

Well, thanks, but I don't feel I invented anything, I must have read about this solution somewhere else some time ago.

Nor do I think it's the perfect and final solution actually... It's just a quick hack that seems to work quite well (it looks like it's working with Sanity's Arte, too!), but I still reckon we can do better. Stay tuned .

[katarakt]

The diode hack is a bad-hack solution. Normally done between pin 34 and 30. It works with every drive for the fake-ready signal but the signal looks like rubbish on a scope. With keirf you can see that ready is immediately there, also not a good solution.

Diode between pin 34 and 10 ...also a bad-hack solution. Have you tried this with x-copy and more than 1 drives?

Still, for real ready solutoins you need a controller ic on a floppy which delivers a real ready OR you have to use the external AmiExtFDD PCB solution which generates a real ready signal for every PC floppy drive (haven't tried this yet, but this should work too).

Diode for sure is NOT the once for all solution

[Turrican_3]

http://www.softpres.org/article:hard...u-257a605p_fdd
http://www.softpres.org/article:hard..._fdd_connector

Is this information accurate?

I'm asking because my Escom/Amiga Technologies A1200 seems to be slightly different: since I didn't know about the motherboard modifications, I actually swapped its drive with a regular C= A1200 one... and it worked!

Does this imply my (Escom) motherboard does NOT need any further modifications, or should I try Sanity Arte to be 100% sure?

Please note my Escom A1200 had a small daughterboard between the floppy drive and its motherboard connector.

[Jope]

Try arte and see if it boots. It is possible that the daughterboard did the pin swap in your machine.

[demolition]

Not all Escoms have that modification. My Escom A1200 did not have any modifications on the MB and also no daughterboard before the drive. The drive is a Panasonic and works fine with trackloaders that rely on the RDY signal.

[Turrican_3]

Thanks guys, I guess I'll give it a try then. :-)

[katarakt]

Test it with keirf amiga test kit.

With this you can test the ready signal and motor on/off function as well as track 0 and track alignement overall.

But, if it shows ready it should be within 200-600ms, if it shows 0-10ms, it's not a real ready signal. If you are between 200-600ms, then 99% sure it's a real ready signal. Probably your pcb generates this what you're mentioned.

[Turrican_3]

That's an interesting "trick" to spot whether a drive is faking the signal or not, I'll definitely try it.

Thanks!