DFR0668 500mA pad engagement
![userHead](https://dfimg.dfrobot.com/dfPortrait2.png)
How do I engage the 500mA pad on the bottom of the DFR0668 unit? I have tried to turn the pad but it seems stuck in place. Please advise, as I don't want to destroy the unit.
![p.name](https://dfimg.dfrobot.com/store/data/DFR0668/DFR0668.jpg)
How do I engage the 500mA pad on the bottom of the DFR0668 unit? I have tried to turn the pad but it seems stuck in place. Please advise, as I don't want to destroy the unit.