Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable query

If you want to ask questions about how the machine works, peculiar details, the differences between models, here it is !
How to program the oric hardware (VIA, FDC, ...) is also welcome.
User avatar
baz67
2nd Star Corporal
Posts: 17
Joined: Thu Dec 02, 2010 11:18 pm
Location: 23
Contact:

Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable query

Post by baz67 » Mon Sep 01, 2014 3:49 pm

Afternoon, folks,

Recently, i've been receiving some great help from those Oric stalwarts Steve Marshall and George Dramcheff/Kirilov and to these chaps, I'm eternally grateful.

Basically, my 3" Microdisc master drive has developed a problem whereby it won't write/init/format.
I've tried countless disks and tried cleaning the head... no joy.

Initially, the PSU was also problematic but we think that's stable now - I've had a sparky take a good look at it (he tutted a bit..."terrible 80s technology" was his conclusion!), but it is powering the microdisc drive fine (gets very hot around the rear heatsink, but there you go... normal, methinks).

Anyhow, cutting to the chase, Steve suggested it might be a good idea to contact George and see if he could help me get a 3.5" pc drive working with the Oric Microdisc as a slave unit. I sourced an old 3.5" PC drive and took it from there.

First, I ran an old PC floppy disc cable from the back of the 3.5" drive to the back of the master microdisc's slave port and then powered the floppy disc from an old PC's PSU.

Basically, the system didn't detect the new drive so I'm assuming my floppy cable is no good (I am not able to perform the vital (I am told) crossed ribbon cable operation (exchange 9 and 13 pins)?

So, guys out in Oric world - is it possible for me to be able to buy such a converted ribbon cable from any of you - ie. a cable whereby the cross over has already been done?

Also, will I need to alter any dipswitch settings inside the Microdisk controller to tell the Atmos that I now have a B as well as A drive (or 1 as well as 0 drive)??

Many thanks in advance for any help on this matter.

Best wishes to all on the forum,

ANDY.

User avatar
iss
Flight Lieutenant
Posts: 488
Joined: Sat Apr 03, 2010 5:43 pm
Location: Bulgaria
Contact:

Re: Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable q

Post by iss » Mon Sep 01, 2014 6:39 pm

There is lot of info about floppies and cables on internet.
IMHO, on this page is short and good explanation.
Wires 10-14 should be twisted (instead 9-13). But I think you need NOT twisted cable and drive configured as 'B'.

BTW, your avatar confuses me...

User avatar
Chema
Game master
Posts: 2030
Joined: Tue Jan 17, 2006 10:55 am
Location: Gijón, SPAIN
Contact:

Re: Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable q

Post by Chema » Mon Sep 01, 2014 7:29 pm

I think you need a flat (not twisted) ribbon cable and either a floppy that could be configured as DS0 (old floppies have jumpers for this) or twist cables 12 and 10 (that I have been told, but I'm not sure).

You also need to configure your original floppy as DS1. You can check here http://www.old-computers.com/magazine/view.asp?r=2&a=12 for more information. The site tells somewhere how to configure the dip switches for this, I think.

Hope this helps.

Edit: just noticed you actually want to set your new floppy as B, so I guess you have to reverse what I said, which was on how to set it as A.

User avatar
baz67
2nd Star Corporal
Posts: 17
Joined: Thu Dec 02, 2010 11:18 pm
Location: 23
Contact:

Re: Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable q

Post by baz67 » Mon Sep 01, 2014 9:25 pm

Many thanks, chaps.
I will look into these pointers/links and I will report back in a few days.
I'm also thinking of just removing the 3" master drive mechanism for now - and swapping it out with the 3.5"... to see if the disk interface 'sees' the drive directly - that's if the edge connectors are compatible.
I'm grateful to your replies - the Oric community lives on - thank you.
ANDY

User avatar
peacer
Flight Lieutenant
Posts: 349
Joined: Wed Jun 09, 2010 9:23 pm
Location: Turkey
Contact:

Re: Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable q

Post by peacer » Tue Sep 02, 2014 7:23 pm

Is there a tutorial page which describe how to connect 3½ disc drive to use with 3" microdisc drive as B: as a slave?

http://www.old-computers.com/magazine/view.asp?r=2&a=12
Here, connecting a 3" microdisc drive to PC ise described in detail but 3.5" drive linked to your Microdisc or Jasmin unit is not given there. Instead, its said that this is explained in CEO-MAG

I am thinking that there was such a page but I could'nt find by googleing..

User avatar
baz67
2nd Star Corporal
Posts: 17
Joined: Thu Dec 02, 2010 11:18 pm
Location: 23
Contact:

Re: Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable q

Post by baz67 » Tue Sep 02, 2014 8:33 pm

Hi Peacer.
I contacted CEO mag but they said they could no longer trace the author of that 3" drive/PC2Oric article namely -

Romual Liné <romualdl@oric-international.org

It's such a shame as he's clearly very knowledgeable but no-one knows where he is now... or where these CEO articles are... unless somone on here knows otherwise!!

Cheers, folks.

Awfully good of you to help - Vive l'Oric.

ANDY

User avatar
peacer
Flight Lieutenant
Posts: 349
Joined: Wed Jun 09, 2010 9:23 pm
Location: Turkey
Contact:

Re: Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable q

Post by peacer » Wed Sep 03, 2014 6:43 am

I see.. Thank you very much anyway :)

User avatar
Chema
Game master
Posts: 2030
Joined: Tue Jan 17, 2006 10:55 am
Location: Gijón, SPAIN
Contact:

Re: Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable q

Post by Chema » Wed Sep 03, 2014 7:26 pm

Did you find this site http://andre.cheramy.net/trucs/lecteur.htm? A bunch of articles about this subject, but all in French :(

User avatar
baz67
2nd Star Corporal
Posts: 17
Joined: Thu Dec 02, 2010 11:18 pm
Location: 23
Contact:

Re: Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable q

Post by baz67 » Wed Sep 03, 2014 8:10 pm

Hola, Chema - many, many thanks.
Those articles look extremely useful... I'll get my school French textbooks out and try translating!
Sincerely, they look very good - informative and the diagrams/many of the technical words are universal in any language.
Que genial!
My very best wishes.
ANDY

User avatar
baz67
2nd Star Corporal
Posts: 17
Joined: Thu Dec 02, 2010 11:18 pm
Location: 23
Contact:

Re: Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable q

Post by baz67 » Sat Sep 06, 2014 11:37 am

Morning Chema/guys,
Just a quick query - one of the PDF files your link took me to contained an extensive lists of 720K FDD which presumably are 'Oric' compatible in terms of disk densities, however I'm trying to use a MITSUMI D359M3 which is listeed as a 1.44mb model...
http://www.amibay.com/showthread.php?26 ... -drive-mod

(This link details how another user has successfuly converted the drive to work with his Amiga - hats off to these splendid retro-engineering guys!)

I am thinking that there is NO WAY such a 1.44mb drive will work with the Oric disk interface, or might I be OK, so long as I don't use HD floppy disks?

PS. George has been in touch and is willing to send me a 'correctly crossed' FDD cable - what a guy - I am very grateful to all you Oric 'magicians' who keep guys like me thoroughly enthralled with our collective hobby of maintaining our highly prized retro beasts from the 80s!

Cheers, fellas - have a good weekend.

ANDY

User avatar
Chema
Game master
Posts: 2030
Joined: Tue Jan 17, 2006 10:55 am
Location: Gijón, SPAIN
Contact:

Re: Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable q

Post by Chema » Sat Sep 06, 2014 1:59 pm

I am using a 1.44 floppy drive with my Microdisc clone with no issues and others have too. But yeah, only 720k discs.

Again the best would be a drive with jumpers to select DS0-1-2-3...

User avatar
baz67
2nd Star Corporal
Posts: 17
Joined: Thu Dec 02, 2010 11:18 pm
Location: 23
Contact:

Re: Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable q

Post by baz67 » Sat Sep 06, 2014 2:57 pm

Thanks again for the prompt reply, Chema.
So, a 1.44mb FDD should be OK and you send me advice on the jumper switch settings.
Sorry to be a pain, but will I need to set these on the microdisc interface and/or the internals of the Mitsumi FDD unit?
I've never done this before so I'm sorry if I need leading slowly...step by step!
LOL.
Many thanks again,
ANDY.

User avatar
Chema
Game master
Posts: 2030
Joined: Tue Jan 17, 2006 10:55 am
Location: Gijón, SPAIN
Contact:

Re: Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable q

Post by Chema » Sat Sep 06, 2014 3:46 pm

I am not sure, to be honest. The whole crossed ribbon thing is to transform a DS0 in DS1 or the other way round *if* you can't do it using the jumpers on the floppy drive unit.

My setup is much simpler, I only have the controller and one floppy drive. I am using a normal flat cable and put the drive in DS0 using the jumpers. Supposedly I could plug another drive in the same cable (it has two connectors, with no cable twists) as long as I can set the drive as DS1.

The thing is that the more modern units did not provide those jumpers and are usually configured as DS1, therefor the need of the crossed ribbon cable.

If I must guess, I'd say that you should use a flat cable and a unit configured as DS1 and it would be B, while the original 3" would be A (master). If you prefer the new one to be the master, it should be configured as DS0 and the 3" as DS1 using the jumpers...

Only if you cannot use jumpers to configure the drive, start testing with the crossed cable.

Anyway testing combinations is not difficult.. And beware I am no expert... I might be completely wrong!

User avatar
baz67
2nd Star Corporal
Posts: 17
Joined: Thu Dec 02, 2010 11:18 pm
Location: 23
Contact:

Re: Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable q

Post by baz67 » Sat Sep 06, 2014 9:41 pm

Thanks again, Chema.
Sound advice - I'll await George's cable, check the connector(s) and dip switches and take it from there/swap around if need be.
I've got a stack more details now to go on - thanks to you and the forum guys.
Will be in touch to update you in the near future.

CHEERS!
Andy

Godzil
Squad Leader
Posts: 755
Joined: Sat May 21, 2011 7:21 pm
Location: Between UK and France
Contact:

Re: Oric microdisk / 3.5" floppy disk CROSSED RIBBON cable q

Post by Godzil » Mon Sep 08, 2014 10:04 am

Sorry it's in French, but a friend of mine made a nice photoset on how to switch a floppy without switches, it was intended to Atari, but we have the exact same problem :) :

http://www.yaronet.com/posts.php?sl=0&s ... &p=1&h=9#9

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest