Repairing the PowerBook 5300
With flaming batteries, chipping paint, and pathetic performance, the PowerBook 5300 is not a computer many remember fondly. Worst of all was the power connector was poorly designed, such that every time an AC adapter was plugged in, pressure was placed directly against the solder joints. In time, the joints failed, resulting in an unreliable connection that made it impossible to charge the battery or run off AC without forcefully holding the power connector at just the right angle to reestablish the connection.
Despite its shortcomings — actually, because of its shortcomings — old 5300's are very affordable. The two PCMCIA slots make it possible to add modems, 802.11b cards, and various other devices. The infrared port, lacking on modern Macs, makes it possible to communicate with devices that newer machines cannot. Any paint that's going to chip has long since done so, the exploding batteries have been replaced, and the system become stable (if not particularly speedy) when upgraded to Mac OS 8. The only serious problem that remains is the solder joints.
A few weeks ago I picked up a $15 PowerBook 5300c that was advertised as having just this issue. To repair the problem, first remove the motherboard by following the directions in Apple's Service Source for the 5300. Once you have the motherboard out, wiggle the power connector. It should be loose. Using a soldering iron and some desoldering braid, remove as much solder from each joint of the connector as is easily possible (see figure below).
The desoldering braid should be placed directly on top of the joint and the iron tip on top of the braid. The iron should be at about 800°F. The solder will melt and be pulled up into the braid. If it doesn't you're probably using a cheap 15-watt soldering iron. A 40-watt iron is ideal.
Once you have most of the solder out, heat the component and board with the iron directly and solder each pin back in. You should now have a firm joint without movement. Reassemble the machine.
Note that this process only fixes the immediate problem — it doesn't eliminate the cause. If you use the machine heavily, the joints will break again, so be prepared to repeat this process in the future.