[Coco] Early disk drive cabling

[Arthur Flexser]

I don't think you need to do anything different for double-sided drives.  I
believe the usual method is to use the Drive 3 line for side selection, so
you sacrifice the ability to have a fourth drive and can have 3
double-sided drives maximum.

Art


On Sun, Aug 24, 2014 at 4:32 PM, Al Hartman <alhartman6 at optonline.net>
wrote:

> Here are some links that might be helpful to you...
>
> http://www.coco3.com/community/2009/09/coco-drives
>
> http://www.vintage-computer.com/vcforum/showthread.php?
> 25767-Floppy-Drive-on-Tandy-COCO3
>
> I would make a cable with 5 connectors:
>
> 1st Connector - to Disk Controller (all pins)
> 2nd Connector - Drive 3 (pull pins 10, 12, 14) (Normally Pin 6 is drive
> select 3, but Tandy decided to use pin 36 which is side select.
>
> I'm not clear how the cable needs to be pinned for double sided drives. a
> Drive 3 needs
>
> the pad for pin 36 cut and jumpered to pin 6.)
> 3rd Connector - Drive 2 (pull pins 10, 12, 36)
> 4th Connector - Drive 1 (pull pins 10, 14, 36)
> 5th Connector - Drive 0 (pull pins 12, 14, 36)
>
> I believe this is correct. To double check, open your drive to see if pin
> 36 is cut and jumpered to pin 6.
>
> I'm also pretty sure that model drive supports only 35 tracks.
>
> I have one I'd like to sell if you are looking for another.
>
> -[Al ]-
>
>
> -----Original Message----- From: Mark J. Blair
>
> I'm putting together an early silver CoCo system in an original-like
> configuration. I just received one of the early 26-3022 drives, in a silver
> case, made by TEC, with the big lever at the lower right corner to release
> the drive door. I also have a 26-3022 controller on the way, purchased
> separately.
>
> I'll need to fabricate a ribbon cable. While I had the drive open to clean
> the head, I didn't find any drive ID jumpers. Did the early 26-3022 drive
> systems have contacts pulled from the individual edge connectors on the
> ribbon cable in order to manage drive IDs, as was done on some other TRS-80
> internal cabling? Did the basic single-drive system originally include a
> cable with edge connectors for additional drives, or did the cable need to
> be replaced when adding drives?
>
> --
> Mark J. Blair, NF6X <nf6x at nf6x.net>
> http://www.nf6x.net/
>
>
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