[MLB-WIRELESS] dead wall warts

[Ratbaggy]

David,

Wallwarts made these days have a thermal "fuse" mounted in the transformer
itself, usually under the layer of tape in thermal contact with the
windings.  To make an educated guess as to what is going on you would need
to know if the primary, secondary or fuse is going open circuit.  If you
peel the tape off, you should be able to find the fuse and do a forensic!

A friend of mine has had one Minitar plugpack fail and that was running on
good mains (replaced under warranty).  I killed one by shorting the output
and that took out the transformer fuse.

Maybe your UPS cutting in and out all the time is producing transients or if
the UPS has square wave output that may be causing problems.  Do the plug
packs run hot?

David Nuttall.

----- Original Message ----- 
From: "David Ashburner" <d_ashburner at hotmail.com>
To: <melbwireless at wireless.org.au>
Sent: Tuesday, October 04, 2005 4:31 PM
Subject: [MLB-WIRELESS] dead wall warts


>
> Kind of strange, I have had 5 wall warts die on me in the last few months.
I
> know they are probably
> not the highest quality parts but still...
>
> 2 x 12 v @ 0.5 amp (Minitar)
> 3 x 12 v @ 1.0 amp (Linksys & Proxim)
>
> when I crack on open and apply 240 to the primary side there is no AC on
the
> secondary winding so it looks like it if failing in the transformer, I'm
> assuming some sort of current surge is blowing the fine wire on the
primary.
>
> I have noticed that the AC power is pretty rough, my UPS is constantly
> trimming the input voltage and you hear it switching in and out once every
> 10 minutes.
>
> anyone else have this happen?
>
>
>
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