[Coco] Powering up our retro systems

[Dave Philipsen]

The links you provided for “reforming” electrolytic capacitors imply that the cap should be removed from its original circuit in order to carry out the process properly. That being said, I have three CoCo 3s that we’re purchased around 1990 (so about 30 yrs old). They had been stored in a garage where temperatures likely varied from around 32F to at least 90F and they all powered up without problem after all those years. 

Dae

> On Jan 26, 2020, at 9:11 AM, wrcooke at wrcooke.net wrote:
> 
>    On January 26, 2020 at 8:31 AM rietveld rietveld <
>   [1]rietveldh at hotmail.com> wrote:
> 
>   A lot of us have a backup coco; and maybe a backup to that backup
> 
>   How often do you power up the spare equipment?
> 
>   How often should we turn it on?
> 
>   The electrolytic capacitors used as power supply filters and for other
>   purposes will deteriorate over time, especially without use.  It's a
>   good idea to power up the equipment (ANY device with such capacitors)
>   about once a year or so.  When in use, the caps "reform" themselves.
>   If the device hasn't been turned on in a while, using lower voltage to
>   power it up is recommended.  If the caps have deteriorated, they can
>   short out, causing a large amount of damage.
> 
>   There are lots of articles on the web about "reforming electrolytic
>   capacitors."  Here are links to some:
> 
>   [2]https://www.6v6.co.uk/vcomp/tech_tips/reform_caps.htm
> 
>   [3]https://www.qsl.net/g3oou/reform.html
> 
>   [4]https://www.diyaudio.com/forums/parts/51492-reforming-electrolytic-c
>   apacitors.html
> 
>   I only briefly looked at those to see if they looked reasonable.  There
>   are some bad ones.  YMMV.  Generally, I use a variac (variable voltage
>   transformer) and slowly raise the voltage to the device over a few
>   hours.  Then let it run for a few hours more.
> 
>   How long should we leave it on?
> 
>   Estimates vary.  Overnight or 24 hours seems to be good.  See above.
> 
>   --
> 
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>   [5]Coco at maltedmedia.com
> 
>   [6]https://pairlist5.pair.net/mailman/listinfo/coco
> 
>   "A designer knows he has achieved perfection not when there is nothing
>   left to add, but when there is nothing left to take away." --  Antoine
>   de Saint-Exupery
> 
>   "The names of global variables should start with    // "
>   -- https://isocpp.org
> 
> References
> 
>   1. mailto:rietveldh at hotmail.com
>   2. https://www.6v6.co.uk/vcomp/tech_tips/reform_caps.htm
>   3. https://www.qsl.net/g3oou/reform.html
>   4. https://www.diyaudio.com/forums/parts/51492-reforming-electrolytic-capacitors.html
>   5. mailto:Coco at maltedmedia.com
>   6. https://pairlist5.pair.net/mailman/listinfo/coco
> 
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