Does the spot you are talking about resemble this?
The red sign that you are talking about is for the backup battery. It is blinking that means that the backup battery which holds the date and time needs to be replaced. It is a button type battery. Check you manual. There is a section for " Replacing Backup Battery". Go to that section and you will get where it is located and steps on how to replace it.
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The manual of cannon MV400 can be downloaded from this link and on page 95 you can find the respective section.
Take your time. I hope this will solve your problem. If you reply I will get notified.
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