[Gllug] Power Supply loaner in West London?

[Chris Bell]

On Thu 23 Sep, Phil Reynolds wrote:
> 

> 
> I am a bit out of your area but there is nothing to stop me bringing you
> a PSU.
> 
   From Sheffield?

> One point to check - I have noticed this on P3 and P4 boards - are all
> the electrolytic capacitors looking normal or is there any kind of
> swelling, corrosion or leakage? I have had three boards go down within
> the last 18 months with this definite problem.
> 
   Is this happening on boxes with well loaded PSU's or just light loading?
Electrolytic capacitors are good at low frequencies but tend to complain
when there is a lot of HF around. The computer relies on steady power rails
despite swiching at very high clock frequencies, while switch mode PSU's can
go unstable with very light loading. It used to be standard practice to add
a small non-electrolytic capacitor alongside to cope with the HF, while
boards with large area multi-layer power rails are supposed to cope better
by acting as a distributed capacitor.


-- 
Chris Bell

-- 
Gllug mailing list  -  Gllug at gllug.org.uk
http://lists.gllug.org.uk/mailman/listinfo/gllug