https://devzone.nordicsemi.com/f/nordic-q-a/5510/vtg-led-turn-redwhat does it mean the VTG led turn red ? but it has no bad effect to my project. In addition, I find a strange phenomenon. I use three 1.5v battery to power my board. The APK in my phone still can scan the Nordic BLE device and can connect it when I turnen-USTelligent Community 13Sun, 15 Feb 2015 06:34:08 GMThttps://devzone.nordicsemi.com/thread/19260?ContentTypeID=1Sun, 15 Feb 2015 06:34:08 GMT137ad170-7792-4731-bb38-c0d22fbe4515:48434441-e289-4b5d-987f-373f9a5c2514xiaoxiao<p>Thank you for your attention, I have resolved this problem. The board&#39;s batteries have dead! what a *** thing, I had changed the batteries a week ago.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/19259?ContentTypeID=1Wed, 11 Feb 2015 17:18:27 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f25853bc-edb2-47c1-a657-9ea0a1e0ffb8Asbj&#248;rn<p>Normally the red light means that you have battery and USB connected at the same time and the S8 switch is in Vsupply position. Could this be what is happening on your board too?</p><div style="clear:both;"></div>