[clug] FM114P Wireless Router printer doover - More from Andrews Emporium 'o free stuff/junk.

Mike Carden mike.carden at gmail.com
Wed Nov 19 00:13:07 GMT 2008


> Others may point out that power bricks rarely die and if they do it
> can indicate that something is amiss inside the unit itself as it
> might be drawing more power than normal.


If the original power supply is of the low cost and slightly weighty
passive transformer (plus rectifier / filter) variety, then death via
excess current draw from the router is not very likely at all.
Usually, the internal resistance of the output circuit in these things
is so high that they have trouble delivering enough current to hurt
themselves, even into a dead short. Usually.

Most of these sorts of power supply have a fusible link in series with
one side of the transformer's primary winding and it's most often the
culprit. If you have a multimeter, or even a continuity tester,
applying it across the mains pins of the thing will show infinite
resistance (open circuit) if the link has blown. Try to keep your
fingers off the pins while you do this, or you may get a lesson in
back-EMF when you unhook if the primary is actually intact. The
dedicated and penniless have been known to crack open such devices to
bypass a blown link, but that's not a course of action to be
recommended to anyone (ahem).

If it's the lighter and more modern switchmode type of external
supply, failure is more likely related to the main switching element
(FET, IC or bipolar transistor) and there's sod-all to be done.

-- 
MC


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