> For the complete documentation index, see [llms.txt](https://commanderhelp.verifone.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://commanderhelp.verifone.com/general-help-guides/general-help/how-to-check-for-power.md).
# How to check for power
#### Use this when a device screen is black, blank, or looks off.
Start with the device that has the issue.
Then follow the matching power-check guide below.
Keywords
**Also called:** device has no power, device is off, black screen, blank screen, power check
**Keywords:** how to check for power, power troubleshooting, device power check, POS no power, Commander no power, UPS no power, Pinpad no power, black screen troubleshooting
### Choose the device
### Quick rules
* Check both ends of every power cable.
* If a device uses a power brick, check the brick too.
* Do not unplug Ruby 2 or Topaz power from the back of the unit.
* Ruby 2 and RubyCI have separate power.
* If a UPS has no output, verify wall power and press reset.
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