Voltage drop/loss of functionality after separating an led strip


I have a pixelblaze 2, and I previously was connecting it to one of these guys. I easily did some tests where I could connect it just with a microusb power and run it at low brightness without issue.

I am working on a project that has the strips separated. I cut along the cut lines, wired a few of these cuts together, and connected. I am now getting a range of issues:

  1. Upon connecting, my voltage goes from 5V to 2.6V.
  2. I only ever get a few of the first leds lighting up, compared to most of the strip before
  3. Most functionality is intermittent/non functional.

I’m a little confused what could cause this change. Is it possible the soldering heated up the leds, causing greater current requirements? Is it dangerous to try to just keep pushing the power supply?

Any ideas for debugging it?

Can you post some clear pictures that show all of your wiring? Also, how many total LEDs are connected to the PB now?

It definitely sounds like a short in the strip somewhere. Double check polarity, not all strips use the same signal placement, and many LEDs connected in reverse can appear as a short.

I would desolder the segments, trying each individually, then assemble and test one bit at a time.

Sounds great, I’ll go ahead and try that out. Here are the pictures, hopefully uploaded in the order of the strip


No obvious shorts or misdirection anywhere, but I’ll try desoldering, unless there’s something obvious.

One of those photos (this one) has the white wire going to +5V and the red wire going to ground.


!! Thanks so much Chris! Amazing how when you look at something enough, even the wrong things look right.

The strip is back to operational :slight_smile:

Much appreciated the help from everyone here. Even though it ended up a simple fix, it was nice to have the support.