On Tuesday, December 8, 2015 at 7:05:55 PM UTC-5, wrote:
OP...good question, yes I have 2 such blankets, one has stopped heating, the other is still good.

I took one apart to attempt a repair. I was expecting to find a small single heating wire fed power at the two ends and maybe a break in the wire or a bad safety device.

But I was surprised to find instead a 2 conductor type of wire that was fed power across the two wires. Apparently the wire contains some special resistive material that connects across the two conductors and heats up all along the wire. In an analogy it is like parallel christmas lights instead of series. Also I think the material is self adjusting such that if a local piece of the wire gets too hot, the resistance goes up and the heat reduces at that portion only. It worked well when it worked, the heat was even.

So i could find nothing wrong with the control or the wiring other than the heating wire had a higher resistance across the two conductor compared to the good blanket. So I can only conclude that whatever resistive material the wire is made out of, it deteriorated over time. There is no single place where the wire is broken, it is just deteriorated over the length.

So I thought i can fix this, simply get some of this special wire and replace it. Well i have not been able to find this wire on ebay or any other place that a consumer could buy say 20 feet.

If I get more information on this special parallel conductor heating wire, I'll post it here.

If anyone else knows anything about it, let us know.

The wire looks like ordinary two conductor with white insulation. It looks like ordinary two conductor wire, but it isn't it has some built in heating stuff distributed throughout it's length that connects across the 2 conductors.



Mark

looks like "self regulating heating cable" is a good search term

http://www.ebay.com/itm/120-Volt-AC-...kAAOSwPYZU6sN-

But that stuff is a bit expensive

Mark