Re: Who owns a 8050/8250 with tandon drives?

Hi Martin,

Thanks for the pictures but no joy I'm afraid. I had 5 x 8050's around 
here, all with Micropolis drives.

1 x 901482-03, 901482-04 and 901483-03 RRIOT
3 x 901482-07, 901482-06 and 901483-03 RRIOT
1 x 901887-01, 901888-01 and 901885-04 RRIOT

Cheers, Rob

On 14/03/2014 17:10, Martin Hoffmann-Vetter wrote:
> Hello Rob,
>
>>> Don't know exactly what looks like tandon drives for 8050/8250 but
>>> they have a different floppy locking system as regular ones.
>>> Micropolis locking system have a sort of rectengular push button. To
>>> load the floppy disk, you push the disk into the unit, then, when you
>>> push (quite heavily) the button, the entire drive mecanism rotates to
>>> complete lock. To remove the floppy, you push (quite heavily) again
>>> the rectengular buton and the entire mecanism rotate back but does
>>> not eject the disk; you have then to pull the buton to eject the
>>> disk.
>> I took a look at the service manual and they all look rather similar
>> from the outside.
> Yes, the Tandon drives are shown as the MPI or Shugart drives. But some Micropolis drives look likes so, too.
>
> An other point is the type label on the rear side. Some units are labeled as 8050M or 8250M. This M means Micropolis or MPI. So if you find a unit labeled with 8050M or 8250M this isn't a tandon drive.
>
> If you look into a drive (where the disc is interted) you can see some differences between the drive types. But that isn't easy. So you must compare some drives.
>
>> I'll venture up into the attic with a screwdriver
>> and a camera and over the weekend to see what I have.
> If you open a 8050 or 8250, you can identify a tandon drive with the analog board. This isn't only on one drive. It's bigger ...
>
> See some picture from inside a 8050/8250 drive:
>
> MPI and Micropolis: http://www.cbmhardware.de/floppy/cbm8050.php
> MPI: http://classiccmp.org/dunfield/pet/h/d8050o.jpg and http://classiccmp.org/dunfield/pet/h/d8050b.jpg
> Micropolis: http://classiccmp.org/dunfield/pet/h/d8250i.jpg and http://classiccmp.org/dunfield/pet/h/d8250b.jpg
> Tandon: http://www.vintage-computer.com/vcforum/attachment.php?attachmentid=12320&d=1363656089 (must be register at vintage-computer.com)
>
> Martin
>
> BTW: If you open some drives and look into, can you look at the DOS roms, too? There are two version from DOS 2.5 (only 8050) with 901482-03/901482-04 and 901482-06/901482-07 and one version of DOS 2.7 (8050 or 8250) with 901487-01/901488-01 known. If you find an other version, it would be great to dump this, too.
>
>
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