> For the complete documentation index, see [llms.txt](https://gsfcorp.gitbook.io/eca/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gsfcorp.gitbook.io/eca/useful-guides-and-info/replace-power-supply-module-in-hot-swappable-redundant-power-supply-psu.md).
# Replace Power Supply Module in Hot-Swappable Redundant Power Supply (PSU)
## Applicability
* ECA4
## Description
* The ECA4 may come configured with optional hot-swappable redundant power supply (PSU).
* The are two power supply modules (PSM) in the redundant power supply, named PSU1 and PSU2.
* Follow the steps in this guide carefully for the removal and replacement of the PSM
***
## Remove Power Supply Module
{% stepper %}
{% step %}
Toggle the switch to 'O' position to switch off the power supply module that you intend to remove.
{% endstep %}
{% step %}
Unplug the power cord.
{% endstep %}
{% step %}
Remove the screw
{% endstep %}
{% step %}
Lift handle and pull out the power supply module.
{% endstep %}
{% endstepper %}
***
## Install Power Supply Module
{% stepper %}
{% step %}
Insert the replacement PSU.
{% endstep %}
{% step %}
Fastern the screw.
{% endstep %}
{% step %}
Connect the power cord.
{% endstep %}
{% step %}
Switch on the power supply module.
{% endstep %}
{% endstepper %}