Basic electronic failure. What am I missing?

[Lockbody]

My daughter bought a set of strings lights for a project. Two thin, copper strands with a low voltage LED every foot, or so, and a control box that does things like fade-in/out, chasing, etc.

While she was attaching it to her project she managed to clip one of the strands after the fourth LED. She twisted the one strand back together, but none of the lights after the fourth would light up. Simple, I think, Something is wrong with the fifth LED so I'll just clip it out and splice. Nope

Loose strand bad? Nope. I got a 9v and it lit right up. Same thing with a wall wart.

Maybe something is funky between the working four lights and the loose strand, so I clipped the four working lights from the leads from the control box and spliced the rest of the lights to the box. No worky.

WTF? The copper wires aren't insulated, so it's not shorted out. If the control box was bad or the batteries weak (not likely, as they're brand new), then why would only the first four LEDs light up and the rest stay dark?

I'm totally confused.

[Lockbody]

And before anyone else posts it...

[Dave Scepter]

4 hours ago, Lockbody said:

why would only the first four LEDs light up and the rest stay dark?

Did you check continuity of the wires after the 4th LED?

[Lockbody]

9 minutes ago, Dave Scepter said:

Did you check continuity of the wires after the 4 LED?

Kind of hard since the two separate wires touch each other repeatedly. I would think continuity was proven when I lit the loose strand up with the 9v.

 

Like these:

[killerteddybear]

Are you sure it's only two wires? If so, how does the chasing effect work?
 

[Lockbody]

1 hour ago, killerteddybear said:

Are you sure it's only two wires? If so, how does the chasing effect work?
 

Two wires, yep.

No friggin' idea. The wife threw the box away, so don't even know what brand it is. All I know is that they got it at WalMart.

[Lockbody]

The lights are different, but the controller is the same. Two wire.

[HAMERMAN]

Each wire likely has a very thin layer of varnish on it for insulation. Twisting the wires back together wouldn't do anything for you since the varnish is still there. If you could hit the twisted section with a soldering iron and solder you can restore the connection because in a setup like this the varnish is meant to burn off under the heat of an iron. You probably got life with the 9V because the tiny amount of exposed copper at the cut end of the wire was touching the battery.

[Lockbody]

33 minutes ago, HAMERMAN said:

Each wire likely has a very thin layer of varnish on it for insulation. Twisting the wires back together wouldn't do anything for you since the varnish is still there. If you could hit the twisted section with a soldering iron and solder you can restore the connection because in a setup like this the varnish is meant to burn off under the heat of an iron. You probably got life with the 9V because the tiny amount of exposed copper at the cut end of the wire was touching the battery.

YES!!! That's got to be it. So simple, and just like a guitar pickup. I can't believe I didn't think of it.

Thanks!

[Lockbody]

HAMERMAN for the win!

My daughter says "Thank you!"

[HAMERMAN]

On ‎4‎/‎12‎/‎2017 at 7:20 PM, Lockbody said:

My daughter says "Thank you!"

Glad to help - she is very welcome.