[Coco] Caring for a CoCo

[Gene Heskett]

On Wednesday 18 November 2009, Boisy G. Pitre wrote:
>I would think that would be an issue with a lot of CoCos and might explain
> some of the "strangeness" that CoCo's exhibit as they get older.
>
>What would be the symptoms of this type of degradation james?

Less than stable operation.  And hum bars in the video would be instant cause 
for replacement of the electrolytics.  All of them at this age are going to 
be suspect.

I'm seeing heat questions.  I battled that too, but cooled it down some when 
I swapped the 512k card out for one of Tony D's 2 megs kits, which uses a 
pair of 1 megs simm modules.  But the real end of the heat problems was when 
I pulled all the psu components off the board in both my cc3 and the 
multipack, and ran a pair of 4 pin trailer connectors out to an old AT power 
supply.  Its fan cooled and loafing with that load along with my stack of 
drives, and the coco3 runs so cool that I have laid a darkroom thermometer on 
the top grill, & tossed a furniture blanket on top of that.  I can come back 
in an hour, or 2 weeks, and the thermometer is maybe 2 degrees above ambient.

In short, the coco's power supply is its own worst enemy.  With the 2 meg kit 
and a 63C09, the only heat source left is the gime chip.

>--
>Boisy G. Pitre
>http://www.tee-boy.com/
>
>On Nov 18, 2009, at 5:19 PM, jdaggett at gate.net wrote:
>> On 18 Nov 2009 at 13:23, Mike Pepe wrote:
>>> I would also consider changing out the electrolytic filter caps in the
>>> power supply, as they do tend to dry out with age and the increasing
>>> amounts of AC ripple riding through the supply can't be good for it.
>>
>> The electrolytics would only be a problem if the unit has sat for several
>> years and not been powered up. Yes the electrolytic materail tends to
>> deform with age and no charge on the cap. What happens then is the ESR of
>> the cap goes way up. This reduces its function as a filter against
>> ripple.
>>
>> james
>>
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-- 
Cheers, Gene
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