I would replace the battery connector cable: [product|IF154-033]
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UPDATE
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Given that we don't have any other place to go (or symptoms I don't know about?) It's the logical and cheapest fix to try. See if you can tighten the screws on the DC-IN port. If it's the outer ring on the plug in jack that has spread, wrap some wire (like muli-strand cord wire) around it and slowly tighten the wire by twisting to close to spread.