[Coco] Powering up our retro systems

[Dave Philipsen]

I read the document (or at least the pertinent parts) and it said, "The 
result is that a higher than normal leakage current will flow when a 
voltage is applied after prolonged storage. As the oxide layer is 
regenerated in use, however, the leakage current will gradually decline 
to its normal level. When designing application circuits, attention must 
be paid to the fact that after storage the leakage current may be up to 
100 times higher than normal during the first few minutes following the 
application of power."

Then under the storage section it said, "If the capacitors have been 
stored at temperatures above +35°C or for longer than above-mentioned 
periods, it is necessary to consider whether the application circuit is 
able to tolerate high initial leakage currents. If this is not the case, 
one should perform the special reforming procedure."

So here's what I glean from the document.  Make sure your power supply 
is designed in such a way that it will tolerate/sustain an initial 
leakage of at least 100x the normal leakage current after the circuit 
has remained idle for some time. If your circuit can't sustain that, 
then you may need to manually reform the capacitor(s). As long as your 
circuit is tolerant of that, the capacitor(s) will reform by virtue of 
their being used after a relatively short amount of time.

And the document reiterates what I said, that high temperatures are the 
biggest culprits. So you can either allow the CoCo power supply to 
reform the capacitors (which it likely has the capacity to do in most 
cases) after a prolonged storage period or you can gradually apply 
voltage starting at a lower potential in the case of the power supply 
not having the ability to sustain the higher leakage currents at its 
rated voltage.

So from what I understand, the only reason to be concerned about the 
CoCo's ability to reform the caps on its own by merely turning the CoCo 
on, is if the power supply doesn't have enough "oomph" to handle the 
higher leakage currents.  And from your statement that the transformer 
is capable of delivering ten amps of power (albeit for a limited time) 
then I would have a hard time thinking that the power supply couldn't to 
that.

Dave





On 1/27/2020 8:05 AM, wrcooke at wrcooke.net wrote:
>     
>
>
>
>
>
>     This document:
>     [3]https://www.tdk-electronics.tdk.com/download/530704/6ad5ed9e1ff4f727
>     c328cb92da2adf2b/pdf-generaltechnicalinformation.pdf
>
>     From TDK, a reputable manufacturer of electrolytic caps, has a great
>     deal to say about the life and storage of them.  It specifically says
>     they are expected to be reformed after storage.  See sections 3.7.7 and
>     7.3
>
>     Best,
>
>     Will
>
>     But that's just me.
>
>     Good luck.
>
>     Will
>
>     References
>
>     1. mailto: [2] [4]dave at davebiz.com
>
>     --
>
>     Coco mailing list
>
>     [3] [5]Coco at maltedmedia.com
>
>     [4] [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 // "
>
>     -- [7]https://isocpp.org
>
>     References
>
>     1. mailto: [8]dave at davebiz.com
>
>     2. mailto: [9]dave at davebiz.com
>
>     3. mailto: [10]Coco at maltedmedia.com
>
>     4. [11]https://pairlist5.pair.net/mailman/listinfo/coco
>
>     --
>
>     Coco mailing list
>
>     [12]Coco at maltedmedia.com
>
>     [13]https://pairlist5.pair.net/mailman/listinfo/coco
>
>     --
>
>     Coco mailing list
>
>     [14]Coco at maltedmedia.com
>
>     [15]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:dave at davebiz.com
>     2. mailto:wrcooke at wrcooke.net
>     3. https://www.tdk-electronics.tdk.com/download/530704/6ad5ed9e1ff4f727c328cb92da2adf2b/pdf-generaltechnicalinformation.pdf
>     4. mailto:dave at davebiz.com
>     5. mailto:Coco at maltedmedia.com
>     6. https://pairlist5.pair.net/mailman/listinfo/coco
>     7. https://isocpp.org/
>     8. mailto:dave at davebiz.com
>     9. mailto:dave at davebiz.com
>    10. mailto:Coco at maltedmedia.com
>    11. https://pairlist5.pair.net/mailman/listinfo/coco
>    12. mailto:Coco at maltedmedia.com
>    13. https://pairlist5.pair.net/mailman/listinfo/coco
>    14. mailto:Coco at maltedmedia.com
>    15. https://pairlist5.pair.net/mailman/listinfo/coco
>