回答“MagSafe power adaptor or other problem?”Oops, I didn't notice your paragraph "After a little while I noticed a really acrid, burning-electrical-insulation-type smell, which seemed to be coming from the MagSafe connector itself. This seems to have become ever so slightly discoloured, so I put it down to a short in the connector itself, and discontinued using it." So clearly something was burnt out. Nevertheless, would replacing the I/O board also solve the problem (at considerably higher cost) if dirt were present and the cause of a poor contact -- is a new female MagSafe connector present on the replacement I/O board?
回答“MagSafe power adaptor or other problem?”No, I don't agree with any advice that suggests that there is a problem with the adapter nor with the laptop. First you need to consider the solution that I describe below: In my experience, the most common reason why an adapter with MagSafe connector fails to light / charge properly is because of dirt collected on the female (laptop) side of the connector, all along the inside corners of its rectangular outline. This dirt prevents the adapter's male connector from sitting properly and establishing and maintaining a good contact. Prove this by taking a suspected defective AC adapter and trying it on a new, clean laptop. It works right? The Apple Store "geniuses" do this all the time, without thinking through and realizing that the problem is dirt on the customer's own laptop! What's the solution? Use a magnifying glass to take a good close look at those inside corners of the female MagSafe receptacle on the laptop, and carefully clean out any dirt that is there. A sharp, thin instrument works best. It may...