The LS3 does not turn on

Either the battery is fully drained > charge!
Or the display driver chip is malfunctioning. In this scenario the LS3 is running but the display stays blank.

This can be checked by searching for it with the App.
First plug in the charging cable, and turn it on (press PWR for 3 seconds).
If not visible, press PWR button for 3 seconds again (maybe it was on an you just turned it off).
If still not visible, press PWR again, and search again with app.
If the LS3 is running it will be listed in the found devices list.
In such a case the PCB (with OLED) must be replaced by a certified LS3 service partner (currently only CMC and LineGrip Corp.)
Note: about 1-2% of all devices of batches 001 and 002 were affected by this “driver chip problem”.

If the display stays dark, AND it is not visible in the App it must be another PCB defect.
In such a case the PCB (with OLED) must be replaced by a certified LS3 service partner (currently only CMC and LineGrip Corp.).

You will find the contacts in this article: My LS3 is damaged, I need repair – who do I contact?