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3.5" and 3" disks on the same cable possible?

Posted: Sat Jan 29, 2011 8:46 pm
by amigajunkie
Hello

I have two Amstrad FD-1 3" external drives. One I would like to canablize to mount a 3" drive and 3.5" drive on the same cable (and neatly mount everything into a twin 5.25 external case).

I note that inside the Amstrad FD-1 external drive their is a circuit board which converts the connections onto a 5.25" cable. I presume I need this little board when mounting the drive into an external 5.25 box?

I would like to incorporate a 3.5" preservation drive (84 tracks), and a 3" Amstrad drive in a 5.25" box as I regularly deal with Amiga and ZX Spectrum +3 machines. Is this possible?

Prior to Kyroflux appearing, I would image Spectrum +3 disks by connecting my Amstrad FD-1 drive onto the motherboard floppy port of my PC, going into bios and setting the drive as a 5.25 inch drive, and then using SamDisk from DOS prompt to image disks for the WOS preservation team. Is anything similar to this necessary when getting the 3" Amstrad drive running under Kyroflux?

3.5" and 3" disks on the same cable possible?

Posted: Sun Jan 30, 2011 12:14 am
by Interceptor
Not sure about this, I had trouble making the drive work unless the board was jumped as single drive mode.

That said once it worked I didn't look further.

I might give this a go myself tomorrow if I get a chance.

Re: 3.5" and 3" disks on the same cable possible?

Posted: Sun Jan 30, 2011 10:35 pm
by amigajunkie
... Please let us know if a 3" and 3.5" drive will work on the same cable as Im holding back on buying a double 5.25" case to mount my kyroflux and drives on until i can be sure they will work on the same cable.

3.5" and 3" disks on the same cable possible?

Posted: Mon Jan 31, 2011 10:28 am
by mr.vince
Basically yes. As long as both drives can be jumpered to the correct ID and you can make the cable fit. Not sure about 3" connector.

Re: 3.5" and 3" disks on the same cable possible?

Posted: Tue Feb 01, 2011 3:22 pm
by philpem
The control protocol for the Amstrad EME-series drives is basically the same as standard 3.5in drives (with the exception of the READY output which most modern 3.5in drives don't provide). All you need to put a 3.5in and a 3in on one cable is a suitable adapter -- from 34pin PC to Amstrad 26pin. Two IDC connectors, a piece of tripad board, some wire, solder and a soldering iron is all you need. If you need a 26-to-26 cable, you can make one out of two IDC connectors and some ribbon cable. A bench vice is the only tool you'll need to put the cable together (and maybe some sharp scissors to cut the cable).

Just watch out -- EME1xx and EME2xx drives use the same power connector as PC drives, but the pin connections are mirrored. Plugging them directly into a PC drive WILL blow the drive control ASIC: this more or less writes off the drive, as the ASICs were custom made for Amstrad and haven't been made in many years. I'm working on a replacement drive controller card but it's a back-burner project, so no definite timeframe. If you're buying these drives from Ebay, make sure to tell the seller NOT to test them!
If they say the access light was half-on when they tested it, the drive might be OK. If it was stuck fully on (i.e. really, really bright), the ASIC has been blown.

3.5" and 3" disks on the same cable possible?

Posted: Tue Feb 01, 2011 4:24 pm
by Interceptor
I haven't had chance to get it confirmed working yet, been one of those weeks again :/

Re: 3.5" and 3" disks on the same cable possible?

Posted: Tue Feb 01, 2011 8:05 pm
by amigajunkie
philpem wrote:The control protocol for the Amstrad EME-series drives is basically the same as standard 3.5in drives (with the exception of the READY output which most modern 3.5in drives don't provide). All you need to put a 3.5in and a 3in on one cable is a suitable adapter -- from 34pin PC to Amstrad 26pin. Two IDC connectors, a piece of tripad board, some wire, solder and a soldering iron is all you need. If you need a 26-to-26 cable, you can make one out of two IDC connectors and some ribbon cable. A bench vice is the only tool you'll need to put the cable together (and maybe some sharp scissors to cut the cable).
When opening up an Amstrad FD-1 external drive the 34 pin PC to Amstrad 26 pin adapter is already inside the Amstrad FD-1 casing; just a case of taking it out and transplanting it into an external box (as im planning to use 3.5" and 3" Amstrad drives simultaneously.
philpem wrote: Just watch out -- EME1xx and EME2xx drives use the same power connector as PC drives, but the pin connections are mirrored. Plugging them directly into a PC drive WILL blow the drive control ASIC: this more or less writes off the drive, as the ASICs were custom made for Amstrad and haven't been made in many years. I'm working on a replacement drive controller card but it's a back-burner project, so no definite timeframe. If you're buying these drives from Ebay, make sure to tell the seller NOT to test them!
If they say the access light was half-on when they tested it, the drive might be OK. If it was stuck fully on (i.e. really, really bright), the ASIC has been blown.
Thank you for reminding me of that. I recall reading somewhere that the power connector on back of 3" drives is mirrored so when using a PC power supply with an Amstrad 3" drive, the power connector needs to be put on upside down. Maybe somebody can just check that piece of information as my memory fades me nowadays.

3.5" and 3" disks on the same cable possible?

Posted: Tue Feb 01, 2011 9:24 pm
by Interceptor
I have just tried an eme-156 here.

It seems that on the untwisted cable the drive responds to the motor command as ds1 but the data and stepping respond as ds0

On the twisted side the motor responds as ds0 and nothing happens on ds1

If I put the jumpers 'together' in single drive mode the drive works fine.

I don't see how it's possible to run this drive alongside another one, unless mr Vince has any ideas?

Re: 3.5

Posted: Tue Feb 01, 2011 9:33 pm
by amigajunkie
Interceptor wrote:I have just tried an eme-156 here.

It seems that on the untwisted cable the drive responds to the motor command as ds1 but the data and stepping respond as ds0

On the twisted side the motor responds as ds0 and nothing happens on ds1

If I put the jumpers 'together' in single drive mode the drive works fine.

I don't see how it's possible to run this drive alongside another one, unless mr Vince has any ideas?
Thank you for testing this hypothesis for us... Any one else want to run some futher tests to try and work around the two drives on one cable?