Re: Strange CBM710 with 3.5" drive

From: Michał Pleban <>
Date: Fri, 14 Jun 2013 11:37:12 +0200
Message-ID: <>

Christian Dirks wrote:

> So it was you who bid me out ... ;)

Oops, sorry. I started buying stuff again, so watch out for me! ;-)

> I wanted to see how the internal floppy drive works.

It is labeled "SMD-150". From what I was able to found on the net, it's
a floppy drive made by Epson, single sided, single density, 180kB
capacity. I didn't even know that single sided 3.5" drives existed? And
why someone would put such a low capacity drive on this mighty machine?

There is a 13-wire makeshift ribbon cable connected to the drive. This
might be a subset of a Shugart connector with only required signals. On
the other side it plugs into a small PCB attached to the expansion
connector. On the PCB there is an EPROM, a SAB2793B floppy controller,
two TTL chips and several discrete elements. I'll try to dump the EPROM

A 4-pin connector is also soldered instead of the extra (otherwise
unused) power connector from the power supply and it powers the floppy.

> 'Elektronikladen Detmold' still exists:
> Maybe someone there knows about the 'GDP 64K' ?

Thanks for the pointer, I'll send them email :-)

Michal Pleban

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Received on 2013-06-14 17:00:08

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