Join the club. :( :) I've had 4 or 5 (yeah I'm a sucker for Sunbeam
blankets) but don't want to be too critical of Sunbeam - they
have replaced several under warranty and replaced one totally.
Thee typical symptoms are that they do tend to get weaker over time, but
some die totally. The weakening may be related to the PTC (Positive
Temperature Coefificnt) of resistance of the wire used as the heating
element. It's self limiting so claimed to be safer since even
scrunching up the blanket should not result in an excessive temperature
rise. However, the change in resistance may not be totally reversible.
I doubt using preheat makes a big difference.
Since the power to the heater is pulse width modulated (around an 80
second cycle - yes, that long!), running at lower heat doesn't
necessarily help either.
When they totally die, I assume it's a bad connection issue, possibly
at the "module" - the wart attached to the connector, which has a
couple of discrete components inside and nothing else.
And I do now record the current used when new. ;-)
Google "Sunbeam blanket problems" or something like. There's a lot
out there.
--
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