[Coco] Unreliable Coco3

[Retro Canada]

you don't need to replace it.

Just find a contact cleaner found in any electronic parts store. apply
it to the contacts and using a folded carton or hard paper will can
clean it. Don't use qtips or they will be stuck in the connectors.

Also take a small screwdriver and push each contact to check if they
are not stuck. It should bend when you insert the screwdriver. Make
sure all contacts are in place again or you could blew you 6809 :P

For the garbage screen, leave the computer on without the controller.
It could be a chip when it overheats it starts to malfunction. You
have an extension 512  right ? Socketed memory chips ? Start removing
and cleaning all memory chips, only reseating them should be enough
but if you see it's corroded  use a nail file to gently clean the
pins. Take care to put them back in the same orientation. There is a
small mark on one of the ends of the chip, it must be aligned to the
PBC marks too. It's is usually a semi-circle or a small circle on the
corner.

If it's a overheating problem, you could use a "well calibrated"
finger to measure the temperature. Bad chips usually but not always
will burn your finger if you stay long on it.

Good luck.


On Mon, Oct 22, 2012 at 9:10 AM, Brian Blake <random.rodder at gmail.com> wrote:
>
> 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
>>>
>>>
>>>
>>> --
>>> Coco mailing list
>>> Coco at maltedmedia.com
>>> http://five.pairlist.net/mailman/listinfo/coco
>>
>> --
>> Coco mailing list
>> Coco at maltedmedia.com
>> http://five.pairlist.net/mailman/listinfo/coco
>
>
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco



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