I haven't had this problem with a SD2, but we have had it with other printers -- usually it breaks around the connector because the crimp is stressing the wire and presents a hard, semi-sharp edge.

We've used a few gauges of wires over the course of the company. We've had SD2s running 10 hour shifts from the beginning with no such wire issues. From what we have observed, this is not a common problem.

So I guess a few other people have had this problem, but I was mentioning it because I had not yet heard of this (i didnt understand what people meant when they said the heater wire broke...I thought they meant connector connections.) It was just a fundamental surprise; I didnt realize it was possible.

the wire connecting my board to the heater cartridge that was flat out broken.  I pulled from both ends and it snaps at the point that was merely insulation.

I had the hot end heater wires fail on one of my printers, too.  I guess the wires they use are not designed for the flexing that occurs during normal printing.  Best to keep a spare set of wires around for the inevitable.

The funny part: you're showing the tubes of ink (from a third party modification to the printer), not the wires going to the printhead.

Whoops! Meant to post this one:

Weird. The only answer I can come up with is that the wire suffered some mechanical stress.

Yeah, because it's low strand count low grade wire, subjected to flexing.

Many others have dealt with this. Jooshs, I think.

A better design would be wire rated for repeated flexing, or a flat flex cable, like what printers use:

EDIT: correct picture two posts down.

I don't know how important this is, but I was chasing a problem for a long time today....I resoldered pin connections, messed with this, and that. Tried to determine if my fet was dead...but then eventually realized that it was merely the wire connecting my board to the heater cartridge that was flat out broken.  I pulled from both ends and it snaps at the point that was merely insulation. I should have realized this sooner, but it never crossed my mind.

TO clarify; i'm saying that the metal strands inside the insulation were completely broken, though externally the wire had no sign of stress. I've never heard of this happening...so I was very surprised when it was the answer to my problems.

Well, that was fixed, and all is well now. But it was very perplexing as I was trying to solve it. Now back to my other printing problems

Weird. The only answer I can come up with is that the wire suffered some mechanical stress.

TO clarify; i'm saying that the metal strands inside the insulation were completely broken, though externally the wire had no sign of stress. I've never heard of this happening...so I was very surprised when it was the answer to my problems.

Well, that was fixed, and all is well now. But it was very perplexing as I was trying to solve it. Now back to my other printing problems