On Thursday, February 23, 2017 at 3:48:20 PM UTC-5, Samuel M. Goldwasser wrote:
writes:

On Wednesday, February 22, 2017 at 11:27:49 AM UTC-5, R2D4 wrote:
I am on my second Sunbeam electric blanket this Winter and it is doing
the same thing as the first one I had-- starts off for a couple of weeks
working correctly, then spends a week getting weaker and weaker where I
have to turn up the controller all the way and even then the heating is
uneven and weak. I was going to return this one too, but before I do, I
wanted to ask if anyone knew of a solution to repair this? Almost seems
like there is a circuit issue somewhere, maybe in the controller, but
who knows. If it were a cheap repair, I'd just keep the blanket after
the low cost repeatable fix. Thank you.

PS: I can't think that they're making that much money on these. I read
the reviews and *many* folks are having similar issues. If a solution
isn't found for the above, I'd appreciate recommendations for a brand/
model that will last. This definitely isn't like the blanket I had
while growing up 25 years ago; that one lasted for 15 years with no
issues.

Same here. My wife and I have used the dual control Sunbeams, and
they do indeed get weaker over time. I'm kicking myself for not
taking a resistance check of the wiring part when new and comparing to
the old. The problem is that the new blanket uses a different
connector than the prev gen, so swapping the controller can't be used
as a diagnosis tool.

Our Sunbeams normally lasted a few seasons getting weaker each year.
Adding a second comforter on top of the regular bedspread is a good
way to trap heat.

This year we bought a dual control heated mattress pad instead of the
blanket and I'm sure it'll suffer the same fate. I no longer put it
on anything above 4 (out of 10) and never use the admittedly handy
preheat feature because it also runs the blanket or pad at 10 for half
an hour before dropping to the preset temp. In any case, manually
preheating at 4 and dropping it to L when I get in bed is enough to
take the chill out of the sheets. I'm hoping that not using the
automatic preheat and adding another comforter on top will extend the
life. Time will tell I guess.

When this one craps out/gets too weak I'll do a post mortem, but I
suspect it uses resistance wire which changes resistance over time.
If the problem is that, then there's no fixing it.

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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I haven't done any real testing Sam, but just spitballing I'd guess that the more the Sunbeam is used, the faster it becomes inert. So, if run at lower temp settings, less heat/time will be supplied by the blanket and the longer it will last (?). I suspect it's decline is not linear, so keeping the temp down by half may quadruple the life..

At least that's my theory and we'll see how this new Sunbeam mattress pad holds up. We had two blankets before this heated pad (both Sunbeam) and both went *very* weak before being replaced. Neither showed any error code at the controller nor went completely cold, so neither suffered a broken wire anywhere. But even at level ten they barely got warm.

This new Sunbeam heated mattress pad we picked up last fall will be used no more than a max of 4 out of 10 (no preheat which does a level 10 for 30 min).