A damaged charging lead can silently destroy a MacBook— and it’s something most people would never think to check.

A year ago I repaired a liquid damaged MacBook and just 2 weeks ago the customer brought it back saying it would not turn on. On inspection I found that this time it had an electrically damaged CD3217 chip. This is a clever chip that your charger or flash drive or whatever connects to when you plug it into a USB port on a MacBook. In most cases of a CD3217 becoming damaged, the culprit is a non-genuine charger. Cheap look-a-like “compatible” chargers commonly sold online often lack the proper filtering components needed to protect your MacBook from voltage spikes caused by poor wall sockets or electrical interference from everyday appliances switching on and off like heaters. I replaced the blown CD3217 which takes about 2 – 3 hours of precision micro-soldering under a microscope and I returned it to the customer. I was horrified to hear that two weeks later the MacBook would not turn on again – the customer was very frustrated and understandably wanted a repair under warranty.

Again, I had to ask – has a non-genuine charger been used? In this case, however, the customer was certain they had only ever used a genuine Apple charger. That told me we needed to look deeper. I asked to see everything regularly connected to the MacBook — including the USB-C charging cable itself.

Using test equipment, I discovered the alarming truth. The Configuration Channel 2 (CC2) wire — which normally carries low-voltage communication signals between the MacBook and the charger — was intermittently shorting against the VBUS power line. That means a wire designed to carry just 0.25 volts to 1.5 volts was occasionally being hit with 20 volts.

That surge is more than enough to destroy a CD3217 chip, a critical component responsible for USB-C communication on each port of a MacBook.

When I carefully removed the outer insulation it revealed internal damage that was far worse than I thought possible.

The red VBUS wire was stripped bare, with broken strands able to short directly into the CC2 line through a pin-sized hole in the yellow insulation. Unfortunately, human nature can make things even worse. When one charging port didn’t work, the owner naturally tried the remaining ports — unknowingly sending damaging voltage through all four. As a result, all four CD3217 chips on the logic board had failed.

Replacing a CD3217 chip is not a simple repair and takes around 2 – 3 hours of precision microsoldering under a microscope — each 6mm square chip has 96 microscopic connections. Repairing all four would mean 8 to 12 hours of painstaking work.

This customer had been unlucky to have a liquid spill a year ago but then really unlucky to damage the charging lead which lead to two further deaths of his MacBook. His only luck was not going to Apple for repair as their solution in every case is straightforward but costly: replace the entire logic board and lose all data in the process. Each of the 3 events would have clocked up £500 in Apple charges.

Fortunately, at UK Mac Repair, we have the specialist tools and expertise to go further. In this case, we were able to safely extract the customer’s data directly from the damaged logic board and transfer it to a replacement — preserving everything and costing less than half of an Apple repair.

It’s this level of attention to detail, technical depth and commitment to saving both your data and your money that makes the difference when your MacBook really matters.