Using a 5.25" Floppy Disk Drive in an A2000

13 August 2018, 09:33

Hey all, I've been trying on and off for the past few days to get a 5.25" floppy drive working in my A2000. I've seen a few people in various forums saying it can be done, and that they did it back in the day since it was possible to store the same 880k on a 5.25" disk as on a 2DD 3.5" disk, and 5.25" disks were cheaper so it was good for people who wanted a huge collection of games.

Well, I currently have two 5.25" drives that I've been trying to use. The first is an NEC FYD051 / TEAC FD-55F-03-U which seems to be a Japanese NEC PC-98 floppy drive, and I've had zero luck with that one. The other one is a TEAC FD-55GFR.

I found this documentation for the FD-55GFR:

http://deramp.com/downloads/floppy_d...20FD-55GFR.pdf

And it's so incredibly poorly written, I honestly can't believe this was allowed!

The jumpers on my 55GFR are placed differently but are more or less the same (I think I'm missing a few, but they seem irrelevant). The information about jumpers (or "straps", as they call them) starts on page 31 of that document. If somebody could take a look at this and attempt to make heads or tails of it then it would be immensely appreciated, since I've just spent the last 2 hours swapping jumpers around frantically trying to get this thing to work. As far as I understand it right now, the drive has to be configured for 300RPM, but I can't figure out how to do that. It also has to be set so that the Amiga can tell when there is or isn't a disk in the drive, which I also can't figure out.

I have the A2000 configured as follows:

DFO = regular 3.5" drive
DF1 = TEAC FD-55GFR 5.25" drive (I made sure to set the jumper on it to DF1)

The 3.5" drive is set to DF0 and connected to the very end of the floppy cable (after the twist), and the 5.25" is set to DF1 and is connected to the connector before it (this one has no twist) in place of a second 2DD 3.5" drive.

No matter what I set the FD-55GFR's jumpers to, the following occurs:

I turn on the A2000 with Workbench 1.3 in the 3.5" drive, and it begins to boot up.
The 5.25" drive seeks during the boot process (doesn't happen when I have a regular 2DD 3.5" drive in its place).
Workbench 1.3 finishes booting and "DF1:BAD" is visible on the desktop, even when there is not disk in the drive - I think this is the main problem. Something to do with a ready signal?? I don't know much about Amigas, I'm an IBM PC guy!
I try initializing the disk and it tries to format and verify cyl. 0, but fails - even when there's no disk in the drive it does the same thing. Again, it seems to not be able to tell whether there's a disk in the drive or not.

So... any ideas? I managed to successfully make a parallel port cable and write 3.5" Amiga disks from a Windows XP PC last night and thought I was on a bit of a roll, but man did that rolling ball hit a brick wall today.

Any and all help is greatly appreciated.

Jope · 13 August 2018, 11:31

Maybe this would be close to what the Amiga expects.

The document is very comprehensive, but as is the case with these drives, there are a huge amount of variants within the same main model, so you really must get a document that matches your particular variant. If you can find all the jumpers listed on the drive, usually the acronyms for the jumpers are the same across different variants for the same manufacturer, so an incorrect document can be helpful.

IU off \
U0 on = activity LED lights up when drive is selected and outputs a ready signal
U1 on /
D0 off
D1 on (Select 1)
D2 off
D3 off
ML off
RY on (ready output at pin34)
DC2 off (DC output at pin 34 OFF, this jumper setting conflicts with RY, it's either RY or DC2 enabled at a time)
LG on (This is a guess, I seem to remember pin2 is pulled high by the Amiga, as it is an active low output of a real Amiga drive. This drive uses it as a density select input and LG strap on + pin high = low density 300rpm mode.)
I off
II off
IS on (DD/HD rotational speed switching enabled, with no change to the ready signal)
E2 on (drive must be selected to get index pulses and data)

You must always use the diskchange command after inserting a disk.

The document refers to the drive being able to output a DC signal on pin 34 (the Amiga must have this on pin 2), but it may be that your actual drive would not really be capable of that because PCs don't need DC for anything. If it has the required hardware for outputing DC, you would be able to disconnect the pin2 (density select) and route the DC signal in there. One pin of DC2 goes to pin 34 and one comes from the circuit that generates DC. Your jumper would go between the DC signal pin and pin2 of the edge connector. You would also have to pull the signal coming from pin2 high on the drive circuit board to match the I/II/IS settings above. Basically you would cut the trace that comes from pin 2, the edge connector side of the cut trace gets your DC signal and the other side of the trace after your cut would get the pull up resistor.

Oh, and no further support expected on my behalf. This is as far as I can go without access to the actual drive. Have fun, it's an interesting learning process ahead of you.

demolition · 13 August 2018, 12:08

I have an A2000 with a TEAC 5.25" PC configured drive that I intended on using as an Amiga drive, so this topic would be relevant for me however I have not made it far enough to actually try it out yet (I need to fix the A2000 first).

Just checking to make sure.. Are you using a proper Amiga-twisted floppy cable and not one designed for a PC?

This is how it should be twisted for the Amiga:

Jope · 13 August 2018, 12:18

The one on the right is the correct twist for the Amiga.

14 August 2018, 02:16

Quote:

Originally Posted by Jope

Maybe this would be close to what the Amiga expects.

The document is very comprehensive, but as is the case with these drives, there are a huge amount of variants within the same main model, so you really must get a document that matches your particular variant. If you can find all the jumpers listed on the drive, usually the acronyms for the jumpers are the same across different variants for the same manufacturer, so an incorrect document can be helpful.

IU off \
U0 on = activity LED lights up when drive is selected and outputs a ready signal
U1 on /
D0 off
D1 on (Select 1)
D2 off
D3 off
ML off
RY on (ready output at pin34)
DC2 off (DC output at pin 34 OFF, this jumper setting conflicts with RY, it's either RY or DC2 enabled at a time)
LG on (This is a guess, I seem to remember pin2 is pulled high by the Amiga, as it is an active low output of a real Amiga drive. This drive uses it as a density select input and LG strap on + pin high = low density 300rpm mode.)
I off
II off
IS on (DD/HD rotational speed switching enabled, with no change to the ready signal)
E2 on (drive must be selected to get index pulses and data)

You must always use the diskchange command after inserting a disk.

The document refers to the drive being able to output a DC signal on pin 34 (the Amiga must have this on pin 2), but it may be that your actual drive would not really be capable of that because PCs don't need DC for anything. If it has the required hardware for outputing DC, you would be able to disconnect the pin2 (density select) and route the DC signal in there. One pin of DC2 goes to pin 34 and one comes from the circuit that generates DC. Your jumper would go between the DC signal pin and pin2 of the edge connector. You would also have to pull the signal coming from pin2 high on the drive circuit board to match the I/II/IS settings above. Basically you would cut the trace that comes from pin 2, the edge connector side of the cut trace gets your DC signal and the other side of the trace after your cut would get the pull up resistor.

Oh, and no further support expected on my behalf. This is as far as I can go without access to the actual drive. Have fun, it's an interesting learning process ahead of you.

Thank you very much for this, I'll give it a shot and report back.

Quote:

Originally Posted by demolition

I have an A2000 with a TEAC 5.25" PC configured drive that I intended on using as an Amiga drive, so this topic would be relevant for me however I have not made it far enough to actually try it out yet (I need to fix the A2000 first).

Just checking to make sure.. Are you using a proper Amiga-twisted floppy cable and not one designed for a PC?

This is how it should be twisted for the Amiga:

The cable that came with my A2000 has that twist right at the end before the final connector (connects to DF0), but the connector before it that usually connects to the 3.5" DF1 drive has no twist. So when connecting to the 5.25" drive, I'm using a converter to go from that DF1 IDE-style 34-pin connector to the edge connector style, and it's straight-through without a twist.

TjLaZer · 14 August 2018, 05:04

The problem is the Amiga does not natively support a 5 1/4 inch drive. Even the Amiga 1020 external 5 1/4 drive does not work out the box. You have to use mount list DOS driver. Maybe that is what you need to do with the internal drive?

demolition · 14 August 2018, 06:37

Quote:

Originally Posted by TjLaZer

The problem is the Amiga does not natively support a 5 1/4 inch drive. Even the Amiga 1020 external 5 1/4 drive does not work out the box. You have to use mount list DOS driver. Maybe that is what you need to do with the internal drive?

I have an external 5.25" drive for the Amiga and it works just like any 3.5" disk drive, at least with my KS2+ machines. Perhaps only the old KS has issues with these drives?

TjLaZer · 14 August 2018, 07:22

Quote:

Originally Posted by demolition

I have an external 5.25" drive for the Amiga and it works just like any 3.5" disk drive, at least with my KS2+ machines. Perhaps only the old KS has issues with these drives?

Which model? The 1020 needs a DOS driver even on KS 2.0+. But I had issues with read/write errors. Only worked reliably on 1.3 for me.

Jope · 14 August 2018, 07:52

The 1020 is a special beast, only 40 tracks.. That indeed needs a mountlist/dosdriver.

The OP's drive is a 80 track drive, it is internal in an A2000, so it is possible to just close JP301 on the motherboard of the computer to enable id stream generation.

I have one of those external 80 track 5.25" floppy drives too. Works just like a 3.5" drive, complete with automatic disk change. There were two models available here in Finland, one called "Master 5A-1" and another by Roctec, RF542C. Mine's the roctec I believe.

http://amiga.unikko.org/C-lehti/jpeg/1989/5/07.jpg

demolition · 14 August 2018, 07:57

I think that mine is the Master 5A-1 (no model name written on it, but it looks just like it). I don't think it requires anything special from the KS since it also works with NDOS disks like cracked games (which is what people were also using them for together with a boot selector so they could boot from the external drive being DF0).

Jope · 14 August 2018, 08:28

These two particular 5.25" units were specifically made to look just like any 3.5" drive. They were moderately popular among enthusiasts around here, 5.25" disks were a lot cheaper than 3.5" at some point + many had a pile left over from the C64 days.

Technically you'd need 96tpi DD disks with these, but in reality most 48tpi DDs will be good enough.

demolition · 14 August 2018, 11:39

Quote:

Originally Posted by Jope

These two particular 5.25" units were specifically made to look just like any 3.5" drive.

Inside my drive I can see a few modifications, for example one wire which is soldered directly to the drive PCB, so I guess this is to get to a signal which is not present at the connector header? I guess DC/RDY would be the main culprits here. I don't have the drive around here so cannot check for now.

Jope · 14 August 2018, 11:50

Could well be, that they used mechanisms that weren't capable of being configured for Amiga compatiblity using jumpers only.

I cracked mine open when I got it (of course), and at least the diskchange detection opto looked like it was there from the factory. Never saw one in a PC drive.

ElectroBlaster · 18 August 2018, 17:51

I have a pair of generic looking 5.25 externals and an oceanic (need to double check as that one could be for the c64?)

But both the generic 5.25's appear to have standard boards inside attached to the drives, I need to look through my stuff as I had to open one of them a while back! a metal sheild came adrift from one of the heads. I took some pictures just need to locate them.

I also have a bunch of amiga disks for it!

Jope · 19 August 2018, 20:04

The Oceanic is definitely for the CBM 8-bits.

13 August 2018, 09:33	#1
DeChief Posts: n/a	Using a 5.25" Floppy Disk Drive in an A2000 Hey all, I've been trying on and off for the past few days to get a 5.25" floppy drive working in my A2000. I've seen a few people in various forums saying it can be done, and that they did it back in the day since it was possible to store the same 880k on a 5.25" disk as on a 2DD 3.5" disk, and 5.25" disks were cheaper so it was good for people who wanted a huge collection of games. Well, I currently have two 5.25" drives that I've been trying to use. The first is an NEC FYD051 / TEAC FD-55F-03-U which seems to be a Japanese NEC PC-98 floppy drive, and I've had zero luck with that one. The other one is a TEAC FD-55GFR. I found this documentation for the FD-55GFR: http://deramp.com/downloads/floppy_d...20FD-55GFR.pdf And it's so incredibly poorly written, I honestly can't believe this was allowed! The jumpers on my 55GFR are placed differently but are more or less the same (I think I'm missing a few, but they seem irrelevant). The information about jumpers (or "straps", as they call them) starts on page 31 of that document. If somebody could take a look at this and attempt to make heads or tails of it then it would be immensely appreciated, since I've just spent the last 2 hours swapping jumpers around frantically trying to get this thing to work. As far as I understand it right now, the drive has to be configured for 300RPM, but I can't figure out how to do that. It also has to be set so that the Amiga can tell when there is or isn't a disk in the drive, which I also can't figure out. I have the A2000 configured as follows: DFO = regular 3.5" drive DF1 = TEAC FD-55GFR 5.25" drive (I made sure to set the jumper on it to DF1) The 3.5" drive is set to DF0 and connected to the very end of the floppy cable (after the twist), and the 5.25" is set to DF1 and is connected to the connector before it (this one has no twist) in place of a second 2DD 3.5" drive. No matter what I set the FD-55GFR's jumpers to, the following occurs: I turn on the A2000 with Workbench 1.3 in the 3.5" drive, and it begins to boot up. The 5.25" drive seeks during the boot process (doesn't happen when I have a regular 2DD 3.5" drive in its place). Workbench 1.3 finishes booting and "DF1:BAD" is visible on the desktop, even when there is not disk in the drive - I think this is the main problem. Something to do with a ready signal?? I don't know much about Amigas, I'm an IBM PC guy! I try initializing the disk and it tries to format and verify cyl. 0, but fails - even when there's no disk in the drive it does the same thing. Again, it seems to not be able to tell whether there's a disk in the drive or not. So... any ideas? I managed to successfully make a parallel port cable and write 3.5" Amiga disks from a Windows XP PC last night and thought I was on a bit of a roll, but man did that rolling ball hit a brick wall today. Any and all help is greatly appreciated.

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13 August 2018, 11:31	#2
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	Maybe this would be close to what the Amiga expects. The document is very comprehensive, but as is the case with these drives, there are a huge amount of variants within the same main model, so you really must get a document that matches your particular variant. If you can find all the jumpers listed on the drive, usually the acronyms for the jumpers are the same across different variants for the same manufacturer, so an incorrect document can be helpful. IU off \ U0 on = activity LED lights up when drive is selected and outputs a ready signal U1 on / D0 off D1 on (Select 1) D2 off D3 off ML off RY on (ready output at pin34) DC2 off (DC output at pin 34 OFF, this jumper setting conflicts with RY, it's either RY or DC2 enabled at a time) LG on (This is a guess, I seem to remember pin2 is pulled high by the Amiga, as it is an active low output of a real Amiga drive. This drive uses it as a density select input and LG strap on + pin high = low density 300rpm mode.) I off II off IS on (DD/HD rotational speed switching enabled, with no change to the ready signal) E2 on (drive must be selected to get index pulses and data) You must always use the diskchange command after inserting a disk. The document refers to the drive being able to output a DC signal on pin 34 (the Amiga must have this on pin 2), but it may be that your actual drive would not really be capable of that because PCs don't need DC for anything. If it has the required hardware for outputing DC, you would be able to disconnect the pin2 (density select) and route the DC signal in there. One pin of DC2 goes to pin 34 and one comes from the circuit that generates DC. Your jumper would go between the DC signal pin and pin2 of the edge connector. You would also have to pull the signal coming from pin2 high on the drive circuit board to match the I/II/IS settings above. Basically you would cut the trace that comes from pin 2, the edge connector side of the cut trace gets your DC signal and the other side of the trace after your cut would get the pull up resistor. Oh, and no further support expected on my behalf. This is as far as I can go without access to the actual drive. Have fun, it's an interesting learning process ahead of you.

13 August 2018, 12:08	#3
demolition Unregistered User Join Date: Sep 2012 Location: Copenhagen / DK Age: 43 Posts: 4,190	I have an A2000 with a TEAC 5.25" PC configured drive that I intended on using as an Amiga drive, so this topic would be relevant for me however I have not made it far enough to actually try it out yet (I need to fix the A2000 first). Just checking to make sure.. Are you using a proper Amiga-twisted floppy cable and not one designed for a PC? This is how it should be twisted for the Amiga:

13 August 2018, 12:18	#4
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	The one on the right is the correct twist for the Amiga.

14 August 2018, 05:04	#6
TjLaZer Registered User Join Date: Sep 2004 Location: Tacoma, WA USA Age: 52 Posts: 1,915	The problem is the Amiga does not natively support a 5 1/4 inch drive. Even the Amiga 1020 external 5 1/4 drive does not work out the box. You have to use mount list DOS driver. Maybe that is what you need to do with the internal drive?

14 August 2018, 07:52	#9
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	The 1020 is a special beast, only 40 tracks.. That indeed needs a mountlist/dosdriver. The OP's drive is a 80 track drive, it is internal in an A2000, so it is possible to just close JP301 on the motherboard of the computer to enable id stream generation. I have one of those external 80 track 5.25" floppy drives too. Works just like a 3.5" drive, complete with automatic disk change. There were two models available here in Finland, one called "Master 5A-1" and another by Roctec, RF542C. Mine's the roctec I believe. http://amiga.unikko.org/C-lehti/jpeg/1989/5/07.jpg

14 August 2018, 07:57	#10
demolition Unregistered User Join Date: Sep 2012 Location: Copenhagen / DK Age: 43 Posts: 4,190	I think that mine is the Master 5A-1 (no model name written on it, but it looks just like it). I don't think it requires anything special from the KS since it also works with NDOS disks like cracked games (which is what people were also using them for together with a boot selector so they could boot from the external drive being DF0).

14 August 2018, 08:28	#11
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	These two particular 5.25" units were specifically made to look just like any 3.5" drive. They were moderately popular among enthusiasts around here, 5.25" disks were a lot cheaper than 3.5" at some point + many had a pile left over from the C64 days. Technically you'd need 96tpi DD disks with these, but in reality most 48tpi DDs will be good enough.

14 August 2018, 11:50	#13
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	Could well be, that they used mechanisms that weren't capable of being configured for Amiga compatiblity using jumpers only. I cracked mine open when I got it (of course), and at least the diskchange detection opto looked like it was there from the factory. Never saw one in a PC drive.

18 August 2018, 17:51	#14
ElectroBlaster Junior Member Join Date: Mar 2002 Location: Exeter, Devon, UK Age: 49 Posts: 1,705	I have a pair of generic looking 5.25 externals and an oceanic (need to double check as that one could be for the c64?) But both the generic 5.25's appear to have standard boards inside attached to the drives, I need to look through my stuff as I had to open one of them a while back! a metal sheild came adrift from one of the heads. I took some pictures just need to locate them. I also have a bunch of amiga disks for it!

19 August 2018, 20:04	#15
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	The Oceanic is definitely for the CBM 8-bits.

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