There are several steps to follow in order to identify the component which is causing the issue.
You can also use the Dell Server Troubleshooting guide.
Table of Content:
There are a lot of different components involved in providing power to a server. Each of these should be checked from the original power source to the server itself:
Here is a list of articles for certain known technical fixes that might correspond to the symptoms you are seeing:
You can also review the PSU How-to page for more information.