Re: Anyone else seen this.

On 05/07/2026 10:28, The Natural Philosopher wrote:
> On 04/07/2026 23:19, jkn wrote:
>>> And.. change the mostly useless power supply Capacitors!..
>>
>> Is this actually true, specifically referring to Draytek routers? Or 
>> just to Set Top Boxen (in which case I probably agree)
>>
> No. And in fact mostly today capacitors are not as prone to failure as 
> they once were.
> 
> There was a period where bad chemistry was taking out millions of them. 
> They have all gone

Yes, especially equipment that came out of S Korea. Often the ones I've 
had to replace have brand names that maybe pretend that they are from a 
well known company such as SamYoung (Not Samsung!). I've generally found 
that the failed capacitors tend to be physically smaller (often the same 
diameter but shorter) than replacements for reputable capacitor 
manufactures.

There is still the 10C rule for electrolytic capacitors where in general 
the life span doubles with every 10C drop in temperature, and shortens 
by x2 for every 10C increase in temperature.

A reputable capacitor manufacture may quote 10,000 hours at 85C which is 
approx 1.3 years if your equipment is operated continuously at 85C. In 
reality well designed equipment would be running at, say, a maximum of 
60C so life expectancy is 5+ years  when operated continuously.

More reputable equipment manufactures would use capacitors rated and 
10,000 hours at 105C or 10,000 hours @ 125C.  Obviously the latter cost 
more and unlikely to be fitted in cheap electronics. However, for repair 
the difference in price for sourcing a one off of the better specified 
capacitor is minimal vs the cost of 85c capacitor.  The recommendation 
is to always go for the capacitor rated at 105C, and with a low Z, low 
equivalent series resistance (ESR) if fitting to a power supply.



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