[Coco] Unreliable Coco3

Brian Blake random.rodder at gmail.com
Mon Oct 22 09:10:35 EDT 2012


Hey David,

The problems with mine started out being intermittent. Then it got to a 
point where and attempt at drive access would trigger the drive LED and 
that was it; shortly thereafter was nothing - this all happened very 
quickly. If you go to the Maltedmedia archives around January of 2010, 
you'll see two threads:

*Re: [Coco] Weird CoCo3 problem*
*
*
*and*
*
*
*Re: [Coco] Weird CoCo3 problem -- AAAARRRGGGGGHHHHH!!!!*

See if you can do any of the recommended troubleshooting suggested 
there. One way to check the cartridge port - do you have any games or an 
Orchestra 90 you could use?

On 10/22/2012 8:49 AM, David Roper wrote:
> Hi Brian,
>
> The main difference between what you've reported and what's going on
> for me is that the drive is responding and doing *some* things, but
> it's as if a signal isn't getting from the drive back to the Coco
>
> Instinct keeps telling me it's the cartridge port
>
> I just wish I had more hardware skills so I could diagnose it and fix it!
>
> - David
>
> On 22 October 2012 22:28, Brian Blake <random.rodder at gmail.com> wrote:
>> David,
>>
>> Check out this post on my blog from a few years ago:
>> http://tandycoco.com/blog/archives/42
>>
>> While mine didn't weird display issues like yours, the floppy drive access
>> problems certainly sound familiar...
>>
>>
>>
>> On 10/22/2012 6:36 AM, David Roper wrote:
>>> So, I got myself a new controller and drive combo (thanks, Nick!)
>>>
>>> .. turns out that the main problem is actually my 512k Coco3 - the new
>>> drive is showing precisely the same behaviour as the old one.
>>>
>>> I've tried the same setup with my Coco2, and everything runs smooth and
>>> perfect
>>>
>>> I suspect something is wrong with my Coco3's cartridge port, and would
>>> appreciate any ideas
>>>
>>> Symptoms:
>>> When loading a cartridge (either through modified multipak or 'naked
>>> in the port'), at least some of the time (1 or two times out of four)
>>> the screen will be filled with garbage (green background, yellow
>>> blocks) or, the entire display will be shifted a half-character to the
>>> left
>>>
>>> If it does load properly -
>>> 'DIR' with an unformated disk in the drive causes 5 'grinds' and an
>>> ?IO error (drive motor stops)
>>> 'DIR' with a formatted disk in the drive causes at most 1 'grind', and
>>> then the drive motor spins endlessly
>>> 'DSKINI0' causes at most 1 'grind', and then the drive motor spins
>>> endlessly
>>>
>>> The above is precisely the same symptoms as my old controller/drive,
>>> and is 100% reproducible. Once again, the drive and controller work
>>> flawlessly on my Coco2
>>>
>>> Any ideas, suggestions, diagnostics? (or replacement Coco3s in Australia?)
>>>
>>> Kind regards,
>>> David
>>>
>>> --
>>> Coco mailing list
>>> Coco at maltedmedia.com
>>> http://five.pairlist.net/mailman/listinfo/coco
>>
>>
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