Hi Vijay,<br>
<br>
I believe you had your question answered in a case but I will also answer it here so it may be useful to others:<br>
<br>
The self-tests test the front-end of the oscilloscopes, any failure here will require a hardware repair. Please make sure any signals and cables have been disconnected from the instrument before running the self-tests.<br>
To set up a repair go to: <a href="https://www.tek.com/en/service-quote">https://www.tek.com/en/service-quote</a>