replace 1571 mech w amiga drive mech ?
ken ross
, i've been thinking has anyone any thoughts etc about replacing a 1571
mech with an amiga drive mech ?
as i came across an old mag with some chap replacing a 1581 mech with a
5.25'' drive ( i'll have to dig out mag !) which made me think of this
idea in reverse as it were .
( which may sound lame i know as it sounds too easy to work !)
a place nearby me adverts replacement drives for A500 quite cheap and my
C128D's drive is tempramental at times
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Dave R.
<1epc11i.145ssf0fj74q4N%ken....@virgin.net>:
>as the amiga disk drive is a direct replacement for the 1581 drive mech
>, i've been thinking has anyone any thoughts etc about replacing a 1571
>mech with an amiga drive mech ?
>as i came across an old mag with some chap replacing a 1581 mech with a
>5.25'' drive ( i'll have to dig out mag !) which made me think of this
>idea in reverse as it were .
>( which may sound lame i know as it sounds too easy to work !)
>a place nearby me adverts replacement drives for A500 quite cheap and my
>C128D's drive is tempramental at times
>
Inside a 1581, you have the advantage of the fact that Commodore used a
(slightly modified) industry standard connector for the drive, the Shughart
(sp?) bus. The 1571, on the other hand, uses three proprietary connectors
like the 1541. I don't know what the Amiga 5.25" drives use internally,
but it's probably just the edge-connector version of the Shughart bus that
PCs use for their 5.25" drives. People have reported success attaching PC
5.25" drive mechs to their 1541s before, but that involved running wires
from the proprietary connectors directly to points on the drive's
electronics. I'm sure connecting a Shughart bus 3.5" drive would require
the same type of work.
--
::::: Dave Ross / Dr. Watson "Yesterday's technology
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:: === tomorrow!"
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Mark T
"Dave R." wrote:
> People have reported success attaching PC
> 5.25" drive mechs to their 1541s before, but that involved running wires
> from the proprietary connectors directly to points on the drive's
> electronics. I'm sure connecting a Shughart bus 3.5" drive would require
> the same type of work.
This is exactly what I want to do. If I could find the pinouts for the 1541
drive mechanism and the PC 3.5" drive mechanism, I could probably do it.
Whaddya think? Anyone ever attempted this before?
--
Mark
Powered by: Amiga 1200T, Apollo 040/40, 2C 32F, 8.4G HD, 24x CD, Z100,
AteoBus+Pixel64+AteoIO, running OS3.9 and loving it!
Dave R.
mr.bigg...@virgin.net (Mark T) wrote in
<3A98DA11...@virgin.net>:
>This is exactly what I want to do. If I could find the pinouts for the
>1541 drive mechanism and the PC 3.5" drive mechanism, I could probably
>do it. Whaddya think? Anyone ever attempted this before?
For a PC floppy drive:
http://www.hardwarebook.net/co_InternalDisk.html
http://www.hardwarebook.net/co_SmallPower.html
I don't know where you could find pinouts of the 1541, but there are
schematics at ftp://ftp.funet.fi//pub/cbm/schematics/drives/new/1541/ .
Personally, I think the project would be more trouble that it's worth, but
it's your drive and your time, so it's your call. Keep us posted. :)
Mark T
"Dave R." wrote:
> For a PC floppy drive:
>
> http://www.hardwarebook.net/co_InternalDisk.html
> http://www.hardwarebook.net/co_SmallPower.html
>
> I don't know where you could find pinouts of the 1541, but there are
> schematics at ftp://ftp.funet.fi//pub/cbm/schematics/drives/new/1541/ .
Thank you!
> Personally, I think the project would be more trouble that it's worth,
Why?! If it works it would be a great way to get a cheap 3.5" drive for a C64!
> Keep us posted. :)
Certainly will.
Ville Jouppi
>
>
>"Dave R." wrote:
>
>> Personally, I think the project would be more trouble that it's worth,
>
>Why?! If it works it would be a great way to get a cheap 3.5" drive for a C64!
Sure it would, but are you prepared for the job ahead of you? I'm not meaning
to discourage you or anything, but you need to connect the signals coming from
the 1571's board straight to the motors and r/w heads of the 3.5" mechanism..
And build converters while you go. It won't be an easy task for sure.
Oh, another way of doing it might be a CBM direct signals ->
shugart-converter.. Then the circuit would be universal and no-one would have
to reinvent those connections ever again. (and it would be easy to connect
whatever shugart device you like)
ken ross
for a C64!
occiloscope etc is realistically impossible but if it could be turned
into a 1581 would be one way of extending equipment life ;->
i've dug out the original mag that was part of my original inspiriation
- twin cities 128 journal #26 ( can't find date !) in which a chap by
name of miklos garamszeghy fitted a 5.25'' drive into a 1581 ( on
reasons of disk cost ! ) - Mark T <mr.bigg...@virgin.net> send me
your snail mail addy and i'll send you xerox of it which may give some
clues etc ?.
the service manuals at deviliki.fi seems to be offline at pesent as
everytime i try i just get timed out :-<
as they've got the service manual for both the 1581 and 1571 which would
a good start to compare connections etc .
as i'm not that far from analogic who can supply amiga a500 disk drive
mechs ( i've not checked out how much electronics are attached to
supplied mech ) which are direct plug in's for the 1581 mechs i'm
inclined to go along that avenue rather than using a PC mech .
Nicolas Welte
> the service manuals at deviliki.fi seems to be offline at pesent as
> everytime i try i just get timed out :-<
> as they've got the service manual for both the 1581 and 1571 which would
> a good start to compare connections etc .
http://www.devili.iki.fi/Computers/Commodore/ is now online as I checked it.
If it is down, they should be mirrored on funet as well.
> as i'm not that far from analogic who can supply amiga a500 disk drive
> mechs ( i've not checked out how much electronics are attached to
> supplied mech ) which are direct plug in's for the 1581 mechs i'm
> inclined to go along that avenue rather than using a PC mech .
I don't see the point in using A500 mechs in a 1571. True, they're plug in
replacements for the 1581, but only for the electrical connector, the eject
button doesn't fit. What is even worse, there exist a whole bunch of
different eject buttons for each drive mech model and each computer or drive
model, so it seems almost impossible to find a proper complete replacement
for a 1581, an A500 or A1200, or whatever other Amiga. I ended up using
hacked PC mechs in my A500 and A1200, they fit just as good as any other
Amiga mech that is not supplied with the correct eject button.
You have to do an extreme amount of hardware hacking to get the A500 drive to
work in the 1571, so why not hack only two extra connections to make a PC
drive work as well? If you design your interface this way, it's not even any
extra work, and it will save you some $$$ (or UK-Pounds, where the hell is
the Pound sign on this PC keyboard? It was there on the 64!), because from
what I saw at the analogic site A500 mechs are not as cheap as PC mechs. Get
inferior mechs for more money? No, thanks, not for me ;-)
Another point why I would never install a 3,5" mech of any kind in the 1571
is the new, incompatible disk format this would introduce. Add this to the
fact that 3,5" disks generally fail much more often than 5,25" disks and you
don't want to do this anymore.
The other aspect of the project is quite interesting, though: Adding a
standard Shugart interface to the 1571. Preferrably the PC version, not the
Amiga version, of course, because this lets you use almost any 5,25" drive
from the junk yard. While it will probably be of little use for repairing ill
1571 drives, it might come in extremely useful if you want to install your
128 system in a tower case, where you will need a disk drive that installs
nicely into a 5,25" drive bay. It also allows you to install the controller
board far away from the drive mech itself, since Shugart cables can be made
quite long without any problems. If you use the original 1571 mech with a
1541 front bezel you end up using the wires from the r/w head which cannot be
made very long or they will pick up all sorts of interference signals.
Nicolas
Ville Jouppi
>>>Why?! If it works it would be a great way to get a cheap 3.5" drive
>>>for a C64!
>yup that's my original thought ! - to realign a 1571 without
>occiloscope etc is realistically impossible but if it could be turned
>into a 1581 would be one way of extending equipment life ;->
What? Turned into a 1581? That's simple.. Put all the parts that are needed to
build a 1581 into the 1571 casing.. They're two totally different beasts, only
a few similar components.
Ville Jouppi
<we...@chemie.uni-konstanz.de> wrote:
>True, they're plug in
>replacements for the 1581, but only for the electrical connector, the eject
>button doesn't fit. What is even worse, there exist a whole bunch of
>different eject buttons for each drive mech model and each computer or drive
>model, so it seems almost impossible to find a proper complete replacement
>for a 1581, an A500 or A1200, or whatever other Amiga.
Buy a fat chinon mechanism used from someone who broke his A500. Direct fit,
and if the drive button won't fit you can take the button from the 1581's
original drive. As far as I remember the A500 fat chinon is a direct fit to
the 1581.
Joe Studer
software.
Axel
Nicolas Welte wrote:
> The other aspect of the project is quite interesting, though: Adding a
> standard Shugart interface to the 1571. Preferrably the PC version, not the
> Amiga version, of course, because this lets you use almost any 5,25" drive
> from the junk yard.
I can almost guarentee losing CGR compatibility. However its not needed for 3
1/2" inch drives.
> While it will probably be of little use for repairing ill
> 1571 drives, it might come in extremely useful if you want to install your
> 128 system in a tower case, where you will need a disk drive that installs
> nicely into a 5,25" drive bay.
I'm sure that the 1541, 1571 drive mechanism is identical to PC drives; only the
on board electronics are different. It is a small matter to trace out the
appropriate connections. However, High density 5 1/4" drives will present a
problem; a rom rewrite is necessary to double write tracks.
> It also allows you to install the controller
> board far away from the drive mech itself, since Shugart cables can be made
> quite long without any problems. If you use the original 1571 mech with a
> 1541 front bezel you end up using the wires from the r/w head which cannot be
> made very long or they will pick up all sorts of interference signals.
>
I've thought about this for some time as a hardware project, however, it is a
part time project. I can almost interface a 65XX to a ISA board, but I run into
the problem with DMA, and I'm not sure whether a NEC 765 chip could be read byte
by byte. If the 6502 is somewhat identical to the Motorolla 6800, there is a
somewhat limited DMA that could be done by holding one of the theta lines high,
probabily theta 1. But the DMA needs to be done in a really short time otherwise
refresh of the registers does not occur. A 6510 could probabily be interfaced
better by somehow tying the DMA signals to tri-stating the 6510.
>
> Nicolas
Ruud Baltissen
only the
> on board electronics are different. It is a small matter to trace out the
> appropriate connections.
For some unknown reasons all 5.25" PC drives I have have running 5 lines to
the head, C= drives have 4 ??? Any ideas?
> I've thought about this for some time as a hardware project, however, it
is a
> part time project. I can almost interface a 65XX to a ISA board, but I
run into
> the problem with DMA, and I'm not sure whether a NEC 765 chip could be
read byte
> by byte.
I already made an interface in 1989 but NOT using DMA. (made a document
about it last week, is freely available, look for email address at my site)
I also managed reading/writing to a 360 KB not using DMA. Stopped
devellopment because I started to use my PC as a kind of
floppydrive/harddisk for the C64, PC-Disk
Groetjes, Ruud
Axel
Ruud Baltissen wrote:
> > I'm sure that the 1541, 1571 drive mechanism is identical to PC drives;
> only the
> > on board electronics are different. It is a small matter to trace out the
> > appropriate connections.
>
> For some unknown reasons all 5.25" PC drives I have have running 5 lines to
> the head, C= drives have 4 ??? Any ideas?
Good Question, I don't know. I started to pull apart one of my damaged 360K
drives to see what it is used for, the only thing I can think of is that the
read and write currents are different. I can make a guess that because the
drive uses two different voltages through the heads for read and write
purposes, it may need two different impeidences for sucessful read and write
operations.
Nicolas Welte
> > The other aspect of the project is quite interesting, though: Adding a
> > standard Shugart interface to the 1571. Preferrably the PC version, not the
> > Amiga version, of course, because this lets you use almost any 5,25" drive
> > from the junk yard.
>
> I can almost guarentee losing CGR compatibility. However its not needed for 3
> 1/2" inch drives.
I'm sure GCR will still work. Before giving technical explantions, it is
enough to see that the Catweasel controller is able to do GCR with those
drives, and after all Amigas can natively use GCR with those drives as
well.
> I'm sure that the 1541, 1571 drive mechanism is identical to PC drives; only the
> on board electronics are different. It is a small matter to trace out the
> appropriate connections. However, High density 5 1/4" drives will present a
> problem; a rom rewrite is necessary to double write tracks.
Why? There's only one problem with HD drives: You lose write
compatibility. And this is not due to the HD drive but due to the 96tpi
head it uses. 96 tpi drives must not write to disks that have been
created in 48tpi drives, or these disks will have read errors when read
back in an 48tpi drive. No other problems will occur.
Nicolas
Nicolas Welte
>
> > I'm sure that the 1541, 1571 drive mechanism is identical to PC drives;
> only the
> > on board electronics are different. It is a small matter to trace out the
> > appropriate connections.
>
> For some unknown reasons all 5.25" PC drives I have have running 5 lines to
> the head, C= drives have 4 ??? Any ideas?
When I installed such a drive in my 1541, I connected the extra
shielding wire (easy to determine which it is) to the GND signal. The
original drives either didn't have a shielded wire or it was connected
to the same pin as another signal.
Nicolas
Axel
Nicolas Welte wrote:
> Axel wrote:
> > > The other aspect of the project is quite interesting, though: Adding a
> > > standard Shugart interface to the 1571. Preferrably the PC version, not the
> > > Amiga version, of course, because this lets you use almost any 5,25" drive
> > > from the junk yard.
> >
> > I can almost guarentee losing CGR compatibility. However its not needed for 3
> > 1/2" inch drives.
>
> I'm sure GCR will still work. Before giving technical explantions, it is
> enough to see that the Catweasel controller is able to do GCR with those
> drives, and after all Amigas can natively use GCR with those drives as
> well.
True, I forgot about that controller (hits self with 2' x 1' plank of pine). However
using the standard floppy (super I/O) card from a PC will not give you the GCR
compatibility.
>
>
> > I'm sure that the 1541, 1571 drive mechanism is identical to PC drives; only the
> > on board electronics are different. It is a small matter to trace out the
> > appropriate connections. However, High density 5 1/4" drives will present a
> > problem; a rom rewrite is necessary to double write tracks.
>
> Why? There's only one problem with HD drives: You lose write
> compatibility. And this is not due to the HD drive but due to the 96tpi
> head it uses. 96 tpi drives must not write to disks that have been
> created in 48tpi drives, or these disks will have read errors when read
> back in an 48tpi drive. No other problems will occur.
Hence the double write issue. A long time ago, now I'm aging myself, if you wanted
to write DD disks with a HD drive with some certainity, you needed to load a DOS
driver to force the HD disk to write double tracks, thus allowing you to read disk on
a DD drive, formatted and written by a HD drive, with some realibility.
Alternatively you could go the other route, like myself, and use the HD disk to use DD
disks to format to 720K.
In my opinion, if you want to use a PC card for a disk controller, you should use it
for compatibility between the PC and a c64, not backward compatibility for the 1541,
etc. Sure you will have problems with programs, but that what star commander was
designed to allieviate.
Ruud Baltissen
> When I installed such a drive in my 1541, I connected the extra
> shielding wire (easy to determine which it is) to the GND signal. The
> original drives either didn't have a shielded wire or it was connected
> to the same pin as another signal.
I even demolished a head to see what wire went to were, did some resistance
measurements but could not interprete the results. So I put everything on a
shelf for times I have nothing to do at all (may be when I'm retired).
So any info from you how to find out what wire has which function or how to
find out is welcome.
Groetjes, Ruud
Axel
Ruud Baltissen wrote:
> Hallo Nicolas,
>
> > When I installed such a drive in my 1541, I connected the extra
> > shielding wire (easy to determine which it is) to the GND signal. The
> > original drives either didn't have a shielded wire or it was connected
> > to the same pin as another signal.
>
> I even demolished a head to see what wire went to were, did some resistance
> measurements but could not interprete the results. So I put everything on a
> shelf for times I have nothing to do at all (may be when I'm retired).
If it is impedence, you not likely to get any real resistance value since it
would be negliable. You would need to measure amperage through the wire over
sucesively higher frequencies of AC current.