The probable solutions listed as follows:
1, Do not connect any HDDS or cameras, User can observe whether it works or not.
If it works, User should check the HDDs or cameras. The Dvr is in good condition itself.
2, If it doesn’t work, it means user should check the power of DVR or change the monitor with high resolution.
3, If user tries all the above steps and no result, please contact your seller for repair.