mrb's blog

Panasonic R3 Power Jack Solder Joint Reflowing

Keywords: hack hardware

Tonight, I had to reflow the solder joint of the power jack on my laptop. In more than 5.5 years of abusing^Husing this Panasonic R3 every single day as my main computer, this was only the second hardware failure I have experienced.

The internal Toshiba 2.5" HDD did fail after 4 years —based on the sounds it started emitting weeks before dying, I suspect mechanical failure and blame myself for roughly handling the machine :-)— and I replaced it with an SSD. But other than that I think these laptops sure do deserve their "Toughbook" brand name...

Back to my problem, when plugging in the power plug, I could notice that wiggling the cable caused the laptop to intermittently lose power. I verified the continuity of the cable with a voltmeter while the adaptor was plugged into the wall, and it looked okay. So I closely inspected the power jack and noticed the central pin could move a little bit; a sign that a solder joint had become weak. I opened the laptop thanks to the same guide I used to replace the HDD with an SSD last year. Fifteen minutes later, after removing 20+ screws, latches, and ribbon cables, I gained access to the power jack and visually confirmed the weak joint. Even when moving the pin to the best position possible, the electrical resistance between the pin and the cable coming out of the jack was still above 40 Ω. Very minor burn marks from undesired arcing could even be seen. Fortunately the whole back of the jack was protected with electrical tape, and the arcing did not seem to have cause any other damage. A quick intervention with my soldering iron to reflow the joint and add a bit more solder easily fixed the problem. I am now typing this blog entry on my rejuvenated R3!