If it's a stand alone card (as in you have TiVo or card ready TV) you can. If this is a Mediacom DCT with a card in it they will have to replace the DCT too (you can take it to your local office and replace it yourself or have a trouble call scheduled).
On a side note, there is not much to do to troubleshoot the card, make sure the signal is fine, add it to the account and pair and activate it. If it doesn't work check account to make sure it's properly set up and replace the card if needed.
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I speak for myself, not my employer.