[Coco] Powering up our retro systems

wrcooke at wrcooke.net wrcooke at wrcooke.net
Sun Jan 26 10:21:17 EST 2020

   On January 26, 2020 at 9:09 AM [1]wrcooke at wrcooke.net wrote:

   On January 26, 2020 at 8:31 AM rietveld rietveld <

   [1] [2]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] [3]https://www.6v6.co.uk/vcomp/tech_tips/reform_caps.htm

   [3] [4]https://www.qsl.net/g3oou/reform.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.


   A bit more information is in Wikipedia:

   However, that article implies anything built after 1980 is safe.
   That's not quite true.  Safe -er, maybe.  But failures are still common
   on equipment built in the 80s and 90s that I know of.


   1. mailto:wrcooke at wrcooke.net
   2. mailto:rietveldh at hotmail.com
   3. https://www.6v6.co.uk/vcomp/tech_tips/reform_caps.htm
   4. https://www.qsl.net/g3oou/reform.html
   5. https://www.diyaudio.com/forums/parts/51492-reforming-electrolytic-c
   6. https://en.wikipedia.org/wiki/Electrolytic_capacitor#Performance_after_storage

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