Modifying PC floppy drives for Amiga use

[acadiel]

I talked to the recycler today (www.atrecycle.com) - they found me a good 15 floppy drives with RDY/DC jumpers/resistors and they also have DS0/DS1 jumpers/resistors.

They have many more floppy drives as well. I'm going to drive up there and pick up the 15 they found for me. If anyone's interested, they have been scrapping the drives, but would be more than happy to find a use for them rather than scrapping them. Send them a note at support@atrecycle.com and tell them Jon sent you - I sent them a link to this thread to show them what we are doing. They'll likely sell them to you for a very inexpensive price and add shipping.

Anyway, I have three or four varieties I'm picking up tomorrow - Compaq, Panasonic, etc. I'll examine them and see if they're workable or not, and then post my results.

[cpiac64]

i modify to 1,76 a drive panasonic, the floppy now is format 1,76, exist an adf or dms 1,76 for test the drive?

i now run crossdos for test 1.44

[prowler]

Originally Posted by cpiac64

i modify to 1,76 a drive panasonic, the floppy now is format 1,76, exist an adf or dms 1,76 for test the drive?

i now run crossdos for test 1.44

Running CrossDOS with a 1.44M floppy disk in the drive should prove that the drive is okay.

However, if you really want to check if it works with a 1.76M AmigaDOS disk, then, if you have Workbench 3.1, just select the disk icon and format it using the Workbench tool choosing High Density Format, which should be enabled with the drive connected to your machine.

Alternatively, you can create a 1.76M .ADF image using WinUAE.

[cpiac64]

crossdos work perfect

floppy under 3.1 formatted 1.76 perfect

now test with original ndos protect game
next test mount in eternal case for verify if work hd

[Boboo_SK]

Originally Posted by cpiac64

crossdos work perfect

floppy under 3.1 formatted 1.76 perfect

now test with original ndos protect game
next test mount in eternal case for verify if work hd

Please show photos! :-)

[acadiel]

Just for kicks and grins, here are the two DSDD drives I installed into the old A2000. (My daughter is playing Lemmings...) I need to download XCopy and try it and see if it works or not with the modified drives.

The trackdisk writer for Amiga Explorer can read/write just fine to the drives, though, so I can read/write ADFs from my PC.

Hello everyone,

I just modified 2 floppy drives JU-257A606P, and one samsung SFD-321B, with tutorials found here, from you, dearest people. But, all drives failed to work. When I power on my Amiga, all three drives start spinning, but failed to boot from floppy disk. When I connect one of the unmodified PC floppy drives, there is no spinning unless I put floppy disk in.

I'm not good in soldering, I have not equipment suitable for this, so I'm thinking that I screw something. But, what could be wrong, having in mind that all three drives after modification start spinning when power on.
I don't have good camera, pictures are blurry, but, as I can see, everything is soldered OK.

Cheers!

PS
first post to EAB, but unfortunately because of problem I have

[whitebird]

Hello,

@Boboo_SK, I had a look at the page

http://www.amigaportal.cz/forum/show...ighlight=arise

Correct me if wrong, but I understand your design is based on the PCFloppy2Amiga project. So I downloaded the original archive from aminet, and looking at the /READY generation logic, the design mistake can clearly be seen: /SELECT concurrently serves as divider's clock and in combinatory production of the output signal. This can result in some transitory signal (identified as "hazard") which causes the low pulses generating a DD identifyng sequences instead of the HD one.

So you should have corrected this mistake by putting a latch on the output...

This is for the HD identification sequence.

Secondly, to halve the rotational speed, did you keep the same principle, which is dividing the oscillator frequency by 2 when HD switch on?

I am guessing what can be the reason it is not working 100% with some drives. I think it can be due to some non linearity: halving the oscillator frequency does not result in 150RPM but with some error percentage which makes the bit rate not beeing 250Kbits/s...

The Power Computing XL uses FPGA which are far more complex. According to me, it does not halve the rotationnal speed but operates by buffering a complete track and so accomodates Paula 250Kbps to the 500Kbps of the drive => It does not operate faster.

Advantage is that it does not require any drive modification and probably works with all PC HD drives. Disadvantage: it requires more complex electronics.

[Boboo_SK]

1. yes, i based on mentioned documentation, i modified logic circuit for there is no problem with generating of HD signal.
2. yes, rate is divided in half, ie 150mpr. problem of reading and writing is jerky rotation of motor, step is not smooth. another problem is that the head of drive is less sensitive.


i tried to programed CPLD circuit which will be compatible with floppy drive CHINON FZ-357a. and i was successful.
Documentation PCFloppy2Amiga include only basic information, realy logic is much more sofisticated.
Programmed GAL is full working 100%. it is actual for sale.

[rampartsagain]

hi everybody i think mfilos if i am not wrong worked out on every issues of the pc floppy drive adapters ,is this another kind of adapter and what is the level of compatibility for it has been exaustively tested ????

[clauddio]

Originally Posted by Boboo_SK

1. yes, i based on mentioned documentation, i modified logic circuit for there is no problem with generating of HD signal.
2. yes, rate is divided in half, ie 150mpr. problem of reading and writing is jerky rotation of motor, step is not smooth. another problem is that the head of drive is less sensitive.


i tried to programed CPLD circuit which will be compatible with floppy drive CHINON FZ-357a. and i was successful.
Documentation PCFloppy2Amiga include only basic information, realy logic is much more sofisticated.
Programmed GAL is full working 100%. it is actual for sale.

that programmed gal you are selling only works with panasonic drives?

[Boboo_SK]

@clauddio

GAL is universal, working with Sony and TEAC drives. Unfortunately, the mechanics just are not very suitable for conversion of HD mode.

[duga]

Originally Posted by acadiel

Mitsumi D359T5 3.5" drive - replace DF0 Chinon in A2000 with this. I removed the bridge from DS1 and made it DS0. I also removed the jumper from DC and change it to RDY. I then jumpered pin #2 to DC on the bottom of the drive.

I have the Mitsumi D359T5, do you have any more precise instructions?

DS1 -> DS0 is easy
DC -> RDY, do you mean "DCH"?
Pin #2 to DC, you mean on the other side of the circuit board?

[cpiac64]

insert a photo of drive

[duga]

Originally Posted by cpiac64

insert a photo of drive

Done and done.

[cpiac64]

move dch to rdy, solder a wire fron 2 to dc and move ds1 to ds0

[protek]

I tried to mod my Panasonic JU-257A606P to Amstrad use tonight. It's a matter of simply setting the DC to RY. Tried to do it without desoldering the motor ribbon with the outcome that I couldn't get the SMD jumper off and broke one of the traces in the motor ribbon. Also couldn't get the ribbon properly desoldered, probably because I had a too small tip in my soldering station. Therefore I couldn't get the PCB out properly.

Ended up fixing the broken trace by bypassing it with a wire and decided to keep on using a shorting jumper in the floppy cable instead of trying to move the SMD jumper. Maybe I should try to find a Samsung unit from somewhere.

[protek]

Status quo is restored with my Panasonic fdd but ended up getting a Samsung unit. That should be easy to modify to Amstrad settings so I can remove jumpers from the floppy cable. I'll keep the Panasonic as reserve.

I've done the Kipper mod on one of two Sony MPF920 drives I bought recently. After some re-orientation of the ribbon cable, it's working just fine. Loading, formatting and writing disks is perfect on my A1200.

Just need to keep my hands steady enough to mod the second one now!

[alenppc]

Originally Posted by mike_cc

I've done the Kipper mod on one of two Sony MPF920 drives I bought recently. After some re-orientation of the ribbon cable, it's working just fine. Loading, formatting and writing disks is perfect on my A1200.

Just need to keep my hands steady enough to mod the second one now!

Virtually no PC stores sell floppy drives anymore. I have been looking on ebay, it is possible to find them at a reasonable price but very few actually have images of the circuit boards/jumpers or even the revison numbers themselves which would help me identify the good ones and I don't feel like buying blindly. I am finding samsungs frequently but they all have different revisions than the ones posted here. How risky is to buy one of those?

There are also Chinons which are the easiest and the best but they are generally quite expensive (we are taking about $40 upwards), so that seems not worth it.