I have a Dell Latitude D510 that went belly up around two years ago. It will run from the battery, however, the wall adapter will neither power the machine nor charge the battery. Once the battery is dead, the machine is dead.

Since it died I've searched repeatedly for solutions. I've tried a new AC adapter and even removed and replaced the DC jack thinking one of the solder joints might be bad. Both to no avail.

After two years of searching I finally found the answer today. Since it's such a simple fix and I had such a hard time finding it I wanted to post the info for others (as it is apparently a common issue with the D510).

-----SOLUTION-----

It seems this is commonly caused by a cracked solder joint at pin 1 on an inductor filter pair (FL2) near the power jack. Pins 1 and 4 are ground and pins 2 and 3 are power. There should be 20V from 1 to 2 and 3. Anything less indicates a cracked joint that is increasing resistance and dropping the supply voltage. Repair simply requires reflowing all four pins with a little added solder for security.

Detailed instructions can be found here. Dell Latitude D510 solder problem