Adding more than one "FDD" to an Acorn 440

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cheshirenoir
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Adding more than one "FDD" to an Acorn 440

Post by cheshirenoir »

Hey Folks,
Yep, I'm still working at the 440. Lovely piece of kit.
I've mounted the gotek in an aesthetically pleasing fashion, and it all works except...
I'm trying to get both the gotek (Drive 0) and the internal Floppy (Drive 1) working together. I followed this guide and made a custom cable that swapped lines 10 and 12 (to make the internal drive Drive 1) and the Gotek is jumpered as Drive 0.
If I run the internal Floppy as Drive 0 with a straight thru cable, it works. If I run the Gotek as Drive 0 with a straight thru cable, it works.
Add the twist and the internal FDD will not work as Drive 1. I have double-checked and triple-checked I put the twist in the right place. I even went as far as checking the schematics.
What I get when I try and access the additional drive is it whirrs for a quarter second and then a "Drive Empty" error.
I haven't found any other guide to adding an additional drive, so it may just be plain wrong. More likely I am misinterpreting things somehow.
If I add the Gotek back in, neither drive will find the contents, both with the same "Drive Empty" error.
If I then UNplug the internal FDD, the Gotek works fine, which suggests at least that much of the cable is fine.
Is there something obvious I am missing? It's RISC OS 3 and I have gone into Configure and the extra drive is in there. I've made the mod for the gotek where pin 1 of the cable is neatly cut. I feel some signal is either getting through that shouldn't, or a second signal needs to be swapped somewhere.
Maybe the FDD controller only supports a single drive after all?

Cheers and thanks in advance.

Chesh
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Boydie
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Re: Adding more than one "FDD" to an Acorn 440

Post by Boydie »

Try:

http://www.apdl.org.uk/riscworld/volume ... /index.htm

Dual-drive A300s were sold as standard, so the hardware’s certainly capable.
Watford and Beebug did buffer boards for extra drives, but AFAIK this was something required for adding 5.25” drives rather than 3.5”.
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cheshirenoir
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Re: Adding more than one "FDD" to an Acorn 440

Post by cheshirenoir »

Yep that's the other part of the guide I followed. For 310 and 400 machines (Mine's a 440, so same generation) it looks, on paper, like all I'd need to do is add the twist to the cable. This, however, isn't working.

It's annoying me that it looks like it should work (According to those articles) but doesn't.

For now I'm not too stressed. The Gotek works well. It would be nice to have the two drives, but isn't critical.

Chesh
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Re: Adding more than one "FDD" to an Acorn 440

Post by acorn_fan »

I’ve been having similar issues trying to connect two FDD on A5000. See viewtopic.php?f=16&t=22585.

My next step was to make up the cable you describe with the 10/12 twist so interesting that you’ve still got the issue. I’ve certainly got the wrong cable now (it’s a PC standard one with incorrect twist).

I’d been hoping to change the FDD jumpers (original floppies not gotek) rather than solve with cable but can’t find anything on that.
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Re: Adding more than one "FDD" to an Acorn 440

Post by Boydie »

I’ve just checked in my dual-floppy A310. The drive cable doesn’t have a twist. Drive ID is conferred via a (very) discreet switch on the side of the drive, which you can’t see/access if the drive’s in the cradle (Drive 1 is on the left in the photo).
E909DA1F-4FC9-4B6D-B0DD-F8E80B8CAE4D.jpeg
Have you tried a straight-wired cable and setting the drive ID on the floppy drive to 1?

Edit: Okay, the lower drive (S/N ending in 1). Why do iPhone photos always get rotated?

Edit 2: The A300 Module Level Service Manual includes the official Acorn fitting instructions for the second drive kit.
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cheshirenoir
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Re: Adding more than one "FDD" to an Acorn 440

Post by cheshirenoir »

Boydie wrote:
Sat May 22, 2021 1:56 pm
I’ve just checked in my dual-floppy A310. The drive cable doesn’t have a twist. Drive ID is conferred via a (very) discreet switch on the side of the drive, which you can’t see/access if the drive’s in the cradle (Drive 1 is on the left in the photo).
Haha. Just came here to post that I'd found the switch (I found a reference to a drive model and googled "Sony "MP-F63W-00D" manual" and the PDF I found showed me the switch). It's still not perfect. There's something funny going on with drive detect but the internal FDD (As 1) and the Gotek (As 0) are properly co-habitating. Only thing is, the FDD came up once with a Drive error 10 and after that it's been "Drive Empty". The Gotek works fine though.

It feels like I'm this close.

Heh.
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cheshirenoir
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Re: Adding more than one "FDD" to an Acorn 440

Post by cheshirenoir »

...and now it's just working. Both drives can be accessed. The FDD is Drive 1, the Gotek is Drive 0.

All I did was screw the case together, I swear!

Acorn_fan. Check your drives! It may be as simple as flicking a switch in an odd place!

Here's hoping it's as easy for you in the end as it was for me.

Thanks everyone! This Archie is becoming super awesome now.

Cheers!

Chesh
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Re: Adding more than one "FDD" to an Acorn 440

Post by acorn_fan »

Great to hear! There is a small switch on my drives (citizen not sony) but it seems to disconnect the drive from the machine (ie notthing happens at all). Will sort cable and see how I get on - perhaps then the switch might help.
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cheshirenoir
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Re: Adding more than one "FDD" to an Acorn 440

Post by cheshirenoir »

Good luck with the cable.

If that doesn't work, and if you can find a model number, going directly to the manual worked for me.
I know in some drives, it's a matter of physical jumpers. In others I have encountered, it's a track that needs to be cut or bridged.
Dump it here and we can go have a look.

Cheers!

Chesh.
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Re: Adding more than one "FDD" to an Acorn 440

Post by acorn_fan »

Thanks cheshirenoir. It's a Citizen osda-75c. I've found manuals for zillions of old floppy drives online but not this one!

I've got the parts for a ribbon cable on order so that's my next task. A manual would always help too. Or if anyone else has two of these drives in one machine please do let me know the jumper/switch settings.
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Re: Adding more than one "FDD" to an Acorn 440

Post by Simon »

I was reading this thread the other day, might be worth checking your +5 volt rail's voltage:

viewtopic.php?t=19855
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Re: Adding more than one "FDD" to an Acorn 440

Post by philb »

Simon wrote:
Sun May 23, 2021 6:38 pm
I was reading this thread the other day, might be worth checking your +5 volt rail's voltage:
I don't think the issue in that thread applies to the A440. If I remember right it (and all the 32-bit machines) drive 5VCMOS levels onto the floppy interface which will be fine with the Gotek as originally populated. It's only the 8-bit machines that output TTL levels.
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