Pixelblaze with output expander. Loud pop

I just powered up the pixelblaze with output expander. Powered by usb. I heard a pop and a fizzle from the LED strip. I’m afraid to try this again incase I have damaged something, what could this be?

Was it working at the time, and working during/after? Obviously a pop and fizzle aren’t good… Did it have a burning electronics smell? Anything hot? Any visible damage to PB or the LEDs?

There are very few things that can pop and fizzle in most LED strips. If/when an LED does fail it usually goes silently, unless there’s reverse polarity or a short or something involved, in which case things tend to get HOT.

The key to safely turning things back on is isolating each component and adding them back in one at a time.

Unplug everything. LEDs from PB, PB from power supply, power supply from the wall.

Plug in your USB power adapter without anything plugged into it. Check for sounds, smells, heat. If it seems OK, proceed.
Plug in PB without LEDs. Does it power on? Does it stay on for several minutes? If so proceed. Set the LEDs to a dim (but not off) brightness and easily observable pattern.
Finally, add the LEDs. If they are working, raise the brightness back to desired levels.

I followed these steps, no heat, no smell of burning no visible damage. When I connect the LEDs to the PB, the orange and blue lights on the PB disappears?

Sounds like a short. Check the LEDs carefully for any apparent damage. Kinks, LEDs, discoloration, etc.

There are 2 runs of LEDs, to test each run I have separated them to test individually without the output expander…

A works perfectly when I connect to PB.

B, which is a lot longer, makes the lights on PB disappear, cannot see any damage/discoloration etc to the LED strip.

Any other things to check or try?

You can try salvaging it by separating the segments (most are joined 0.5M segments) and finding out which has the short.nthen you can cut and keep going, down to a single pixel.

Ok thank you, I’ll try this tomorrow