+MacRorie Posted May 27, 2015 Share Posted May 27, 2015 Many years ago, I had a XF551 that I had upgraded to be able to be both a 5.25" drive and a 3.5" drive. I seem to recall I had to install a switch to go between them, but I could be wrong. I also seem to recall having to piggyback a ROM onto of another ROM on the motherboard. I know CSS had a much nicer version as well. My question is this: Can this still be done? If so, where might I find available parts? Thanks -Mac Quote Link to comment Share on other sites More sharing options...
+bob1200xl Posted May 27, 2015 Share Posted May 27, 2015 Are you sure you want to go to all that trouble? I did a hack like that, but I found it was more useful just to use two drives in the SIO, rather than a single drive with two mechanisms. Basically, you need to burn a 27128 with both 5.25 and 3.5 code in it - switch between devices by toggling A13 and directing the D0 select line. Some configurations power the drives on and off, but I just use a separate power supply for the second drive. Quote Link to comment Share on other sites More sharing options...
+MacRorie Posted May 27, 2015 Author Share Posted May 27, 2015 Are you sure you want to go to all that trouble? I did a hack like that, but I found it was more useful just to use two drives in the SIO, rather than a single drive with two mechanisms. Basically, you need to burn a 27128 with both 5.25 and 3.5 code in it - switch between devices by toggling A13 and directing the D0 select line. Some configurations power the drives on and off, but I just use a separate power supply for the second drive. Well, here's the deal: I have this Epson dual floppy drive that I want to purpose for just this thing. It decreases the footprint and, well, kinda looks cool as well. I mean, I could do two, but this seems more streamlined. 1 Quote Link to comment Share on other sites More sharing options...
BillC Posted May 27, 2015 Share Posted May 27, 2015 Well, here's the deal: I have this Epson dual floppy drive that I want to purpose for just this thing. It decreases the footprint and, well, kinda looks cool as well. I mean, I could do two, but this seems more streamlined. epson-sd-800-1.21.44-mb-combo-dual-floppy-drive-sd-800-slot-1.24.jpg From what I've found the SD800 uses a HD 1.2MB 5.25" mechanism, there are issues when using HD drives with SD/DD disks. Quote Link to comment Share on other sites More sharing options...
+bob1200xl Posted May 27, 2015 Share Posted May 27, 2015 Yes, you cannot use those Epson drives in an XF551. Wish you could... Bob Quote Link to comment Share on other sites More sharing options...
+MacRorie Posted May 27, 2015 Author Share Posted May 27, 2015 Yes, you cannot use those Epson drives in an XF551. Wish you could... Bob Drat & Double Drat! Quote Link to comment Share on other sites More sharing options...
+Larry Posted May 27, 2015 Share Posted May 27, 2015 Yes, you cannot use those Epson drives in an XF551. Wish you could... Bob What part(s) don't work? Sure, a HD 5.25 is problematic with DD disks, but don't they read ok, and doesn't the 3.5 work ok? Atarimax used to sell these combo drives, IIRC, but I don' t know what mechs. he used. Larry Quote Link to comment Share on other sites More sharing options...
+bob1200xl Posted May 27, 2015 Share Posted May 27, 2015 1.44 drives work OK in an XF551, IF they can density switch. The problem is the 5.25 drive. It is 80 tracks and the stock XF551 is only 40 tracks. Reading a 360K disk requires double-stepping on a seek. Then you still have a drive that can only read. You have to double the clocks to run 1.44meg or 1.2meg - not an easy task, although I seem to remember someone doing it. Maybe AtariMax found some 360K dual drives? Bob Quote Link to comment Share on other sites More sharing options...
BillC Posted May 27, 2015 Share Posted May 27, 2015 The Floppy Board for the BlackBox is supposed to be capable of 1.2/1.44MB operation, and also 1MB 8". Quote Link to comment Share on other sites More sharing options...
+bob1200xl Posted May 27, 2015 Share Posted May 27, 2015 For that matter, the 1050 could do 1.44/1.2 with a little hacking. Bob Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted May 27, 2015 Share Posted May 27, 2015 I found a Teac FD-505 in my parts boxes, but I guess that would have the same issues... Quote Link to comment Share on other sites More sharing options...
papa_november Posted June 2, 2015 Share Posted June 2, 2015 (edited) Running two drives off of the XF551 controller needs more than a ROM swap - the drive select lines for the second drive aren't hooked up. There's a couple of unused lines on the 8050 that could be used for that. The nicer CSS upgrade essentially does this, though the way it does it is unnecessarily complicated due to copy protection weirdness. I don't even think you can order the kit anymore, but nobody's worked out how to reproduce it. All of the combo drives out there are high-density and aren't going to work well. The best way to hook two drives up is to leave the original mechanism as-is, run an extension floppy cable out of the case and rig up the 2nd drive as a "slave" drive. It doesn't have to be ugly; you can put the second drive in it's own case and use extension connectors to clean up the floppy ribbon mess. The Percom drives worked much like this; the first drive you bought had the controller in it and every drive you added thereafter was just a plain mechanism in a metal box. Edited June 2, 2015 by papa_november Quote Link to comment Share on other sites More sharing options...
morelenmir Posted June 3, 2015 Share Posted June 3, 2015 For that matter, the 1050 could do 1.44/1.2 with a little hacking. Bob Could you elaborate on this Bob - maybe via PM if you feel it would hijack the thread. Quote Link to comment Share on other sites More sharing options...
+bob1200xl Posted June 3, 2015 Share Posted June 3, 2015 The 2793 controller in a 1050 was designed to do 180K (our 90K SS Atari format) SD, 360K DD, and 1.2M HD. You would need a larger sector buffer and a faster clock to do HD. Maybe more than a little hacking... Bob Quote Link to comment Share on other sites More sharing options...
cwilbar Posted June 3, 2020 Share Posted June 3, 2020 Reviving an old thread.... Why couldn't a dual mech like that EPSON be used, if you were willing to use this drive to not read original Atari diskettes (40 track). With the 5.25" HD mech you can do 80 tracks at DD, giving 720K. You could use Quad Density floppies (if you could find them), but I've never had any issues back in older PCs doing custom format 720K 5.25" floppies on DD media. The only thing is you'd want to make sure the drive was using 300rpm, and not 360rpm. And without the additional drive select logic (and firmware to control it), you'd have to use a switch on the drive to switch the ids of the 3.5" vs 5.25" drives. But you could probably just use the 720K firmware for 3.5, as you'd use the same format on the 5.25" drive in this case as with the 3.5". Not sure ultimately how useful it would be, but I can't see why it couldn't be done. With modified firmware, you could even theoretically double step the stepper on the HD 5.25" drive to gain read compatability with Atari diskettes, but it wouldn't be a good idea to ever write a 40 track disk unless you were writing to a blank disk formatted with the 5.25" 80 track drive and didn't interchange with regular drives (track (head) width is smaller on the 1.2HD 5.25" (or QD 5.25" drives). I wish that they had manufactured a 360K 5.25"/720K 3.5" combo drive (which would be perfect as an XF551 upgrade), but to the best of my knowledge none were ever made as the dual drives came out well past the intro of high density diskettes.... there wouldn't have been a demand for a dual drive DD unit. Quote Link to comment Share on other sites More sharing options...
+Larry Posted June 3, 2020 Share Posted June 3, 2020 I've got one of the CSS dual-drive XF kits with the 3.5" also cased. I don't use it/them, because I find the XF551 to be much less useful than a 1050 Happy. (Love that track buffer!) I need to get it out and check it over and take a couple of pics. Maybe I'll entertain offers, if anyone is interested. 1 Quote Link to comment Share on other sites More sharing options...
andymanone Posted June 3, 2020 Share Posted June 3, 2020 1 hour ago, Larry said: I need to get it out and check it over and take a couple of pics. Maybe I'll entertain offers, if anyone is interested. Yes, please, that would be great ?! Thanks, andY Quote Link to comment Share on other sites More sharing options...
Simba7 Posted February 5, 2021 Share Posted February 5, 2021 On 6/2/2020 at 11:43 PM, cwilbar said: Reviving an old thread.... Why couldn't a dual mech like that EPSON be used, if you were willing to use this drive to not read original Atari diskettes (40 track). With the 5.25" HD mech you can do 80 tracks at DD, giving 720K. You could use Quad Density floppies (if you could find them), but I've never had any issues back in older PCs doing custom format 720K 5.25" floppies on DD media. The only thing is you'd want to make sure the drive was using 300rpm, and not 360rpm. And without the additional drive select logic (and firmware to control it), you'd have to use a switch on the drive to switch the ids of the 3.5" vs 5.25" drives. But you could probably just use the 720K firmware for 3.5, as you'd use the same format on the 5.25" drive in this case as with the 3.5". Not sure ultimately how useful it would be, but I can't see why it couldn't be done. With modified firmware, you could even theoretically double step the stepper on the HD 5.25" drive to gain read compatability with Atari diskettes, but it wouldn't be a good idea to ever write a 40 track disk unless you were writing to a blank disk formatted with the 5.25" 80 track drive and didn't interchange with regular drives (track (head) width is smaller on the 1.2HD 5.25" (or QD 5.25" drives). I wish that they had manufactured a 360K 5.25"/720K 3.5" combo drive (which would be perfect as an XF551 upgrade), but to the best of my knowledge none were ever made as the dual drives came out well past the intro of high density diskettes.... there wouldn't have been a demand for a dual drive DD unit. I'd love to do this to one of my XF551's as well as the drive itself was severely damaged during shipping. I have a Teac FD-505 and both drives are individually selectable via the board in the back. Mine uses the card edge connector instead of the pin connector. Quote Link to comment Share on other sites More sharing options...
wildstar87 Posted March 26, 2021 Share Posted March 26, 2021 (edited) I happen to have one of these drives that I have hung onto (Epson SD800), and it looks like from the documentation I have found, there IS a jumper to set rpm on the 5.25 mech to 300 rpm. So I wonder if 720k on 5.25 is possible? I don't see why it couldn't use HD disks formatted as QD either. Edited March 26, 2021 by wildstar87 Quote Link to comment Share on other sites More sharing options...
+bob1200xl Posted March 26, 2021 Share Posted March 26, 2021 No, you can't use HD diskettes, no matter what. You can use 720K 5.25 drives, though, with DD diskettes. Same setup as a 3.5 80 track 720K. I did some QD disks way back when, but switched to 3.5 after a while. Bob 1 Quote Link to comment Share on other sites More sharing options...
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