[Coco] Good news: my CoCo 3 is back to life!

[Mark Marlette]

Joel,

Not sure what a WD-1791 is but you are right I almost forgot!!!!!!!!

james?

Mark



Quoting Joel Ewy <jcewy at swbell.net>:

> Mark Marlette wrote:
>> Joel,
>>
>> MB8877A was a 5v drop in replacement for the +12v WD1793, otherwise
>> you would need a MPI for that device.
>>
>> SY6591...that is it...No datasheet on that one at Cloud-9's
>> repositiory... :(
>>
>> I knows there was a mod for the J&M to work on the CC3.
>>
>> Mark
>>
>     Well, the one I have I got second hand (in fact, it came to me in a
> hacked-up standard full-length black plastic drive controller case with
> a Hard Drive Specialist sticker which was about 1/3 torn off so somebody
> could get to the screw.  So it's possible that it was modified before it
> got to me.  But if so, it was a _very_ subtle modification, as I see no
> jumper wires soldered on anywhere, and all the solder joints on the back
> side look original.
>
> And just this morning I checked it out on a CoCo 3.  I used it to load
> up a saved Sockmaster hi-color picture, and it worked like a charm.
> Maybe the modification was for 2MHz operation.  I didn't check that out.
>
> As for a data sheet, I think the SY6591 may be a second source of the
> WD-1791.  I bet James Daggett could confirm or refute that...
>
> JCE
>> Quoting Joel Ewy <jcewy at swbell.net>:
>>
>>> L. Curtis Boyle wrote:
>>>> On Mon, 05 Mar 2007 08:31:49 -0600, Boisy Pitre <boisy at boisypitre.com>
>>>> wrote:
>>>>
>>>>> Gents,
>>>>>
>>>>> Not to put too fine a point on it, but FD-500 controllers will also
>>>>> work at 5v.  I think it's a very older, specific model number of disk
>>>>> controller that requires 12v and hence, the MPI.
>>>>>
>>>>> Boisy
>>>>>
>>>>
>>>> The very old, full size controllers that came with original full
>>>> height, really long grey 35 track single sided drives were the 12V
>>>> controllers.
>>> FWIW, I have a 26-3029, a 26-3129, a J&M (says JFD-COCO rev.A on the
>>> PCB), a Disto Super Controller, and a couple Super Controller IIs.  They
>>> all work on the CoCo 3 without an MPI.  (And none of them are an FD-501
>>> :) )  My 3029 has an MB8877 FDC with a WD9216 data separator.  The
>>> controller in the J&M is an SY6591.  All the rest use the 28-pin WD1773.
>>>
>>> Mike Pepe notes in an email on this list on 8/2/06 that the original
>>> controller (the one that required 12V on the bus) was the 26-3022.  So
>>> that should be the only one you would need to plug into the MPI to use
>>> with the CoCo 3.
>>>> Ironically, the only ones that could properly handle hi-density (1.2
>>>> or 1.44 MB) drives with some modifications to the controller.
>>>>
>>> This fall Mike Pepe modified his  3029 for high-density and posted a few
>>> messages about it on this list.  Last I recall he still needed to
>>> finalize the software/firmware modifications.  His notes are here:
>>> http://www.doki-doki.net/~lamune/computers/coco/hd-floppy/
>>>
>>> JCE
>>>>
>>>> --L. Curtis Boyle
>>>>
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>>>
>>>
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>>
>>
>>
>>
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