[Coco] Unreliable Coco3

[David Roper]

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
>>
>> --
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>
>
>
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