Modifying PC floppy drives for Amiga use
 

Yesterday night I noticed I had a Panasonic JU-257A606P sitting on my shelf..

I remembered that there was an article about that on Aminet regarding how to use it with the Amiga. So, let's download that and see.

It seems the article deals with a very old revision of the A606P, one that I've never seen in the wild.

Naturally the component positions are totally different in these that I've seen.

Oh well, the document told me enough. Get _RDY to pin 34 and _DC to pin 2, make the drive answer to DS0 instead of DS1.

So, judging by the grainy shot, I did the same as the author. I found the place where DC/RY switch is supposed to be, moved the SMD jumper from the DC position to RY and soldered a small wire from the DC pad to pin 2 on the data connector. Then I found the DS 0/1 switch position and moved the jumper block from DS1 to DS0. Slap the bugger back together and plug it into the A1700 that is conveniently without a top cover.

My trembling hands insert Sanity's Arte, a demo that is known to require the ready signal.

It works! Yay.

In case you didn't understand my written instructions, here's an illustration on how the SMD jumpers and wire are supposed to go:

http://jope.fi/ju257/ju257-modded.jpg

So how to tell which one to get?

http://jope.fi/ju257/ju257-detail.jpg

Notice the flexi cable that goes to the stepper motor. It has to go to the right for the above illustration to apply. This is if you feel that you cannot work it out on your own for a different PCB.

So what do I do today? Go down to the recycling center (it's open every day of the week :-D) and buy 10 A606Ps, taking care to get the same PCB revision as the one I had success with. I also purchased two that had different PCBs, one with the flexi cable going left and one that has a connector for the stepper motor.

The one with the flexi going left worked. Naturally the switch positions are different, but you can hopefully work it out on your own.

The one with the connector for the stepper cable didn't work, even though I tried to measure all the "switches" and verified that they are in the same position. Not a big deal, I can handle the financial loss. Perhaps it was broken to begin with or perhaps it just isn't Amiga friendly. :-)

I think that the best success will be on drives that have only two positions for the DC/RY switch. The one that failed had four positions there.

http://jope.fi/ju257/ju257.jpg

Eight drives, ready to be plugged into an Amiga. Anyone want to buy some? I'm probably going to ebay a few, but I'm also open for offers directly. These are great for aftermarket towers. (DS1 versions available per request)

I got rather quick at this.. 5mins per drive after a bit of practice. :-D

If you're wondering where three of them went, one is in my broken drives pile and two are in the A2000T.

These also work nicely in a dual drive configuration for a big box Amiga. If you want it to be DF1, don't swap the DS jumper. Have a cable with only wires 4-6 twisted. DF0 is DS0 and DF1 is DS1. Remember to close the "DF1 present" jumper on your motherboard.

Oh, please recommend other software that needs the ready signal! I'd like to test them more thoroughly. I have verified that Arte will not boot past the boot block without a ready signal.

@jope

A Great DIY post!!!! dankie!!!!

Has anybody else tried this mod? I have a spare JU-257A606P, so I tried it, but the drive will not read any disks. My A500 seems to recognize the drive, it does click, and does try to read a disk when I put one in, but it wont boot. The original drive does boot from the same disks I'm testing with.

Unfortunately I didn't test the drive in my PC first, so I don't know if it was working or not (though I'm pretty sure it was a working pull). Any ideas?

Are the floppy disks you trying DD (720K) or HD (1.4M) ones?

I had a similar problem with a modded Panasonic JU-257 and my 880K-formatted HD diskettes. I solved it by gluing a piece of plastic above the DD/HD sensing microswitch.

Yeah, put some sticky tape around the HD detect hole if you are using HD disks.

A quick solution that one might come to is to just simply bridge the HD detect switch permanently, but this kills diskchange.

All of the disks I tried are DD, so there is no HD detect hole in them. I made the same modification to a Samsung SFD-321B drive, as it also can be configured the same way, but it doesn't work either. When I put a disk in the Amiga tries to read it (click, click, click), but cannot. I think there might be a timing issue. Both of the drives I have are vairly new, perhaps they are built to a slightly different spec than older drives.

Ah, you didn't mention that you used a completely different mechanism.

Unfortunately I've never seen that one, but I have had similar experiences with other drives than the Panasonic this thread talks about.. I didn't really bother wasting my time with them that much, as the JU257A606P was a very common PC drive indeed.

If you have the time and energy to invest, then you might want to try scoping around with a known good drive and this one that doesn't work. I wouldn't, but I already said that. :-)

I've now tried a third drive, another Samsung SFD-321B. it also does not work. I'm sure this was working as I pulled it from a PC that was working last month. Now I have three drives modified (1 Panasonic, 2 Samsung) that don't work in my Amiga :(. Later on I'll undo the modifications so I can test them in a PC.

I'll have to track down some more Panasonic drives because I have 4 Amigas and only two working drives, both are original and old.

EDIT: All four of the floppy disks I was testing with are bad, including my original WB1.3 disk. It appears that my modified Panasonic drive did the damage. Both Samsung drives work wonderfully! I used them to copy a working Zany Golf disk, and boot from it (original and copy). But when I tried to boot the copy from the Panasonic drive, it did not work, and that disk is now unreadable.

I'll take pictures of the modded Samsung drive and post them soon. They were easier to mod than the Panasonic drive (larger solder pads).

As promised, more eye candy! The label below is from the first drive I modified. The second one has the same model number, but is a REV.T1 part. The PCB inside both drives is virtually identical.

http://www3.telus.net/narmi/Label1.jpg

The modifications are the same as for the Panasonic drive. Change the unit number from 1 to 0 via the DS1/DS0 jumpers, change pin 34 to RDY from DC by moving a zero-ohm resistor, and connect DC to pin 2.

http://www3.telus.net/narmi/CircuitMods.jpg

The DS1/DS0 jumper is just a solder blob, I used a solder wick to remove the original blob, then I added another blob on the correct jumper. Pin 2 is connected to a jumper that is not used, so I used one of its pads to connect the DC signal rather than soldering to the connector. It's neater this way. Obviously I noticed the pad after I cut the wire to size :).

I found the manual for this drive on the Amiga floppy project blog. If the manual can be trusted, all revisions of this drive should be moddable, good news since this can still be purchased new. It can even be found with a black faceplate, if you have a black case.

Hey that's cool. Very easy mod too, no need to unsolder the stepper motor cable like in the Panasonic. :-)

Jope, can I get a copy of that demo from you (the one that requires the RDY signal)? I bought and modded two more drives today ($2 each, why not?) and I'd like to test them a bit more thoroughly.

EDIT: Never mind, I found it on Aminet.

there is no need to modify any pc floppy disk drive to make it works on the amiga

a simple modification of the floopy'data cable is the easiest solution:

it works fine I tested

http://aminet.net/docs/hard/PcF2AmF.lha

Some work with the 2-34 swap, but not all. The prefect (and neat) solution is to do real mods to the drive. :-)

I'm sure lots of things will work with the cable trick, but it's too easy for me. I like to open things up and tinker :). In fact, if the mods were more difficult, I could probably make some money selling modified drives. AmigaKit wants $30 for a new drive, though they include a cable.

I think the best solution is using a real amiga drive..cause lots of games not works using that PC drives modifications...idem problem with escom A1200'drives....

there's a hardware hack on aminet for the escom' A1200 drives...maybe that hack is needed also for the 34-2 swap to make the PC drive compatible with all games....I will check that one day when I have time

bye

We have same thread on czech amiga portal.
If anybody needs translation of some hack just ask.
They are all tested and works.

http://amiga.probers.info/forum/forumdisplay.php?f=129

Hi, Laser!

You are wrong. The modifications illustrated here are 1:1 functional Amiga drive replacements, full compatibility. Not comparable to the Escom A1200 drives, which were missing the READY signal. The mods we have shown here have that READY signal and have been tested with software that refuses to boot on an unmodified Escom A1200..

I'd appreciate it if you read what is written in the threads you reply to.

Here's my approach on the YD-702D-6037D A .. I know Chain's forum has a different approach, but try both and see what works for you.

Remove all jumpers except set the ry/dc jumper to ry and ds jumper to ds0

http://jope.fi/drives/yd720d6037d//ye-jumpers.jpg

Remove shortcut block P12 from the pcb and solder a wire from the jumper block's DC pin to the pin 2 side of the P12 solder pads

http://jope.fi/drives/yd720d6037d//ye-modded.jpg

ah sorry...Im vague sometimes I have no cure
OK
if you are looking for software that requires ready signal:
I remember that the game lemmings 1 (cracked version with trainer) not worked on my modified drive,also not worked the game Troddlers (2 disk version /cracked/no trainer),ehhh..Sirius 7,(not remember very well... but you can try)

btw, How a data cable can be modified to make a full compatible amiga drive with ready signal?

It cannot be done, since the ready signal is not present on the 34-pin connector of a PC drive. Some drives (those posted in this thread) have a ready signal available on their PCB which can be routed to the correct pin on the 34-pin connector.