Friday, March 19, 2010

Repairing a Dell Vostro Power Jack

I recently had a job that involved a broken power jack on a Dell Vostro notebook. The middle barrel of the jack broke and was causing the contacts to touch. When the adapter was plugged in, the jack made a sparking sound and caused the power adapter to short out. The customer was told by Dell and a few other sources that the problem involved the motherboard or the power adapter.

The problem was simply the poorly designed power jack/plug combination whose major fault is the distance the plug sticks out of the machine. This makes it hard to use the machine on any soft surface or tight spaces as pressure is applied to the plug which in turn puts pressure on the jack. Because of the length it sticks out, the pressure applied to the plug is multiplied inside the jack and the solder joints and plastic of the jack become loose and break over time. Symptoms of a broken jack are a loose connection, flickering screen, battery not charging, no power at all, and shorting out the power adapter.

I needed to gain access to the jack. This involved dissembling the notebook down to the motherboard. Most notebooks are put together pretty much the same. There is either an access panel to gain access to the keyboard screws which should expose the LCD, keyboard, WIFI antenna wires, and trackpad connections.

From Dell Vostro power jack repair

Most WIFI cards are under a small access panel found on the bottom of the laptop. Take note of which wire is goes where and unplug them.

From Dell Vostro power jack repair

Remove any screws that hold the keyboard down and unplug it. Unplug the LCD panel and take note of where the wires run. Remove any screws that hold the LCD panel on and remove it.

From Dell Vostro power jack repair

Locate the remaining screws on the bottom of the machine and remove them. These will remove the palm rest and reveal the motherboard and power jack.

From Dell Vostro power jack repair

To keep track of where the screws go I drew the top and bottom of the machine and placed the screws on the diagram.

From Dell Vostro power jack repair

Closeup of the backside of the power jack. The 3 pins in the middle are on the center barrel which completely broke away from the rest of the jack. From repetitive abuse, the contacts on the center barrel bent and were creating a dead short even when the cord was plugged in. I un-soldered the wires and removed the center barrel, straightened out the contacts, and aligned the barrel where it belonged.

From Dell Vostro power jack repair

From Dell Vostro power jack repair

I melted some plastic where plastic had broken out of and secured the rest of it with some epoxy. To ensure that the barrel doesn't move I also epoxied all the contacts to each other as well as the back of the whole jack. Once the barrel was stationary, the jack no longer shorted out the adapter.

From Dell Vostro power jack repair

I re-assembled the notebook to the point where I could test it and plugged it in. The battery began to charge and the machine powered up! I un-pluged it and plugged it back in a few times to ensure it would hold and operate correctly, which it did. I re-assembled the rest of the machine and tested it a few more times. About five hours worth of work and the machine was back up and running! No new motherboard (ahem Dell) and no new power adapter required. The customer was more than happy!