Amiga.org
Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: J-Golden on March 08, 2005, 08:19:37 PM
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Anyone know of a good site with Floppy drive specs,
compairisons, pros/cons, etc.?
Looking to get a HD Floppy for my A4000T (not A4000D towered).
TANKZ!
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On a related note, I would like to know if I can use an A4000D floppy drive in my A4000T.
I want a spare A4000T floppy drive. Any advice /suggestions / horror stories?
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X-ray wrote:
On a related note, I would like to know if I can use an A4000D floppy drive in my A4000T.
I want a spare A4000T floppy drive. Any advice /suggestions / horror stories?
Sure you can. The first thing I did when I got my A4000T was to throw out the Escom PC-drive hack and stick a real FZ-357A in there, along with a FZ-354 as DF1:
Just remember to remove the PCB Adapter thingy as well.
As for specs... AFAIK there is only two original HD Floppy drives for Amigas: The Chinon FB-357A (tall ugly thing) and FZ-357A (normal size drive). If you're up for some hacking, have a look at
http://www.inf.mit.bme.hu/private/fz357/
This explains how to modify a normal FZ-357 to a 357A
-Paul
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@ PaSha
What is the difference between the 357A and 354? Tried to Google it but got no joy.
And why do we have these little PCBs in our A4KTs?
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The 357A is a HD drive, and the 354 is a DD drive.
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heh, so no such thing as a easy fix for getting an Amiga HD floppy eh? That stinks...
PLEASE let us know when you Do have thta link fixed. ;) wanna atleast look at 2 C if there is an easier way to get a HD floppy...
J-Golden
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X-ray wrote:
@ PaSha
What is the difference between the 357A and 354? Tried to Google it but got no joy.
And why do we have these little PCBs in our A4KTs?
The little PCB makes a PC HD drive work&behave almost like a Amiga DD drive (AFAIK it just swaps a few lines, the PC floppy pinout is just slightly different from the Amiga pinout, IIRC two pins are swapped), though it is reported to be incompatible with hardware-banging software.
http://www.amiga-hardware.com/download_photos/a4000tfloppyadaptor1.jpg
The Chinon FZ-354 is commonly found in C= A1200s and quite a few external drives. It looks the same as the FZ-357A, (identical bezel/button) so I chose it as DF1: instead of an old FB-357A (tall ugly HD drive) for cosmetic reasons.
-Paul
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@ PaSha
But what I don't understand is if we have these PCBs why can't I just plug in any old PC drive? And if I took the PCB out, would I then have a machine that behaves exactly like an A4000D...would the floppy header be the same?
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X-ray wrote:
@ PaSha
But what I don't understand is if we have these PCBs why can't I just plug in any old PC drive? And if I took the PCB out, would I then have a machine that behaves exactly like an A4000D...would the floppy header be the same?
Yes, you can plug in any old PC drive, and this drive will operate as a 880 kB DD Amiga floppy. It will not, however, read 1760 kB HD Amiga disks, because it doesn't slow down to half speed like a 'real' Amiga HD floppy drive (Chinon FB-357A/FZ-357A, that's what the 'A' is there for).
The reason for Escom using this hack, was to save time and money. It would simply take too much time and money to have someone produce special/custom Amiga FD's (like C= did)compared to hacking standard PC-drives to fit.
Since the A4KT was designed by good old C=, the floppy header is a proper Amiga one. Remove the small adapter PCB, and you have one 100% normal Amiga floppy header (that behaves exactly like in a A4000D), on which you can stick any Amiga FD, in fact, two of them, provided you make the cable correctly (swap pin 4 with 6('In use 1' and In use 0' and pin 10 with 12('select 0' and 'select '), jumper both drives as DS0, ie don't touch the jumpers) for DF1:, and set J250 to the right position.
OFF: No second internal floppy or second floppy (DF1:) is High Density 1.76MB
ON: Second internal floppy (DF1:) is Double Density (880K)
Most A4000Ds were shipped with a floppy cable that had pins 3&5 swapped instead of pins 4&6. And since 3&5 are both GND, it didn't really make a difference...
http://wonkity.com/~wblock/a4000hard/inflpins.html
From http://wonkity.com/~wblock/a4000hard/flcbprob.html
Many (perhaps most) A4000s were shipped with improperly-wired floppy cables. These cables had wires 3-5 twisted, instead of wires 4-6. These cables will work fine for a single drive, but will not properly connect a second drive. To use two drives that are both jumpered as DS0, the floppy cable should have both wires 4-6 and 10-12 twisted. A cable with only wires 4-6 twisted will require the drives to be jumpered as DS0 and DS1.
-Paul
Edit:
The differences between Amiga and PC FDs:
Pins 2 & 34 are swapped, 'Ready' and 'Diskchange'
The 'Diskchange' signal is not used on PCs, and the 'Ready' signal is used differently. Just try reading from an empty FD on PC... The drive will start spinning and making noises, before Windows realizes it's probably empty.
Whereas on the Amiga, the diskchange signal informs WB of the inserted disk and it pops up on WB. Try accessing an empty drive, and WB already knows it's empty.
(The above might not be 100% accurate, but this is the basic idea)
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IIRC, Amiga HD floppys are supposed to have 2x lower RPM (150 instead of 300)
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@ PaSha
Back in 1996 I bought a plain floppy drive from a PC fair and tried to use it on my A4KT and it didn't work.
I just did some experiments again. I took the floppy drive out of my PC and put it in the A4KT: no joy. The access light doesn't even come on and I get the 'unreadable df0' icon in Workbench 3.9.
Just for giggles I put the A4KT floppy on the PC and the same thing happened...no access at all. Whether there is a disk in or not, Winblows says please insert a disk in a:
The A4KT drive is a MITSUMI model D359T5 (Newtronics Co. LTD).
The PC drive is an ALPS ELECTRIC (made in Malaysia). The only number on it that could be a model number is DF354H090F.
So...what gives?
Edit: I didn't change any jumpers on the Amiga side, just changed one drive for the other. Same with the PC. And the cables are keyed so I can't connect them wrong even if I want to.
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I don't know why your Amiga floppy doesn't work in your PC, if it is in fact a PC drive, but I do know that many PC drives are in compatible with Amiga no matter what you do.
Most likely there has been something additional done to the Amiga floppy drive in order to make it work with Amiga, something that needs to be done on the actual floppy drive and not on the cable side by using a PCB.
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I tried a A500 disk drive in one of my PC's and it worked
It read/writed 720k DD disks.
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I have a Chinon357A (HD drive) on my 4000 and an Amtrade hack called "The Real HD Fix by T.Hirsch" (http://www.amiga-hardware.com/showhardware.cgi?HARDID=381) to use Dell (external models) or Teac (internal models) PC floppy drive. My Real flopy fix (green pcb, not red as on BBoAH) is used with a modified floppy drive Teac FD235-HF...
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So, just to clairify, almost any PC Floppy will work in my A4000T as long as I use a cable that has pin 4 & 6 changed.
It will only work as a low density floopy drive though unless you find a PC drve that will spin @ 150 RPM. instead of 300 RPM.
To get two PC floppies to work in an Amiga 4000T without moving jumpers, I also need to change pins 10 & 12 on my floppy cable.
Cable, I can do, what about Floppy drives other then the one Commedore used that will spin @ 150 RPM? are there others out there?
J-Golden
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X-ray wrote:
@ PaSha
Back in 1996 I bought a plain floppy drive from a PC fair and tried to use it on my A4KT and it didn't work.
I just did some experiments again. I took the floppy drive out of my PC and put it in the A4KT: no joy. The access light doesn't even come on and I get the 'unreadable df0' icon in Workbench 3.9.
Just for giggles I put the A4KT floppy on the PC and the same thing happened...no access at all. Whether there is a disk in or not, Winblows says please insert a disk in a:
The A4KT drive is a MITSUMI model D359T5 (Newtronics Co. LTD).
The PC drive is an ALPS ELECTRIC (made in Malaysia). The only number on it that could be a model number is DF354H090F.
So...what gives?
Edit: I didn't change any jumpers on the Amiga side, just changed one drive for the other. Same with the PC. And the cables are keyed so I can't connect them wrong even if I want to.
You might want to change some jumpers on the drive itself.
PC drives are jumpered as DS1 by default.
The Mitsumi drive for your A4000T is jumpered to DS0 with an SMT resistor (pop the bottom cover off, and you'll see the jumper pads next to the 34pin connector.
The TEAC in my PC is jumpered to DS1 the same way. Cost reduction = SMT jumpers
It might be this...
-Paul
-Paul
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Hmmm... seems my post was a bit messy.
J-Golden wrote:
So, just to clairify, almost any PC Floppy will work in my A4000T as long as I use a cable that has pin 4 & 6 changed.
No. Swapping pins 4&6 is for using two Amiga FD's
To get two PC floppies to work in an Amiga 4000T without moving jumpers, I also need to change pins 10 & 12 on my floppy cable.
Same as above. I doubt that using two PC drives is possible, even with the Escom adapter thingy.
Cable, I can do, what about Floppy drives other then the one Commedore used that will spin @ 150 RPM? are there others out there?
J-Golden
As for 150 RPM drives, I believe the C= custom Chinons are the only ones.
-Paul
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Check this one out, it explains some of the differences between PC & Amiga FD's
ftp://de.aminet.net/pub/aminet/hard/hack/PCFloppy2Amiga.lha
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@ PaSha
My PC drive has just solder blobs, very small, on a very small gap. This isn't one I can jerk around with, but next time I'm at the fair I'll pick up a drive for £5 and test it.
It annoys me that even though we have these adapter PCBs there must still be all this fiddling under the cover.
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It could perhaps be possible to use a PC-style floppy cable, with pins 10 through 16 twisted for drive A: (aka DF0) with the PC drive in your Amiga (with the adapter PCB still in place, ofcourse). You could also try your Amiga drive (the Mitsumi) on the 'untwisted'/straight-through connector in the PC cable (the connector meant for B:)
No guarantees here, but this should solve the DS0/DS1 problem. I believe the small Escom PCB solves the ready/diskchange differences only.
If you do shop for a drive, get a really old one with proper jumpers on it. Much easier to fiddle with...
-Paul
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Chaps...
I am still looking for a working spare floppy drive for my A4KT. If anyone is selling one, I am interested. (it would be a bonus if it is a HD drive). I am having no luck with PC drives.
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I have an AmTrade HD floppy in my A1200. Not cheap, but it works with everything I've thrown at it and it was new. SoftwareHut probably still has some in stock.
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> Escom PCB
is there a photo of this on the internet anywhere?
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Darth_X wrote:
> Escom PCB
is there a photo of this on the internet anywhere?
http://www.amiga-hardware.com/download_photos/a4000tfloppyadaptor1.jpg
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thankyou :-D
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just one more thing,
pasha said Amiga uses custom/special FDDs, but thats not true at least not for DD drives. Amiga uses 'Shugart standard' and most other computers have used it too (like ZX Spectrum +3, Acorn). its IBM PC that uses 'special drives'.