1
\$\begingroup\$

enter image description here

As you can see, the one on the top is burnt. Whenever I plug the power adapter into the wall, the component releases a puff of smoke and the adapter instantly shuts itself off. The damage to the component was caused by an issue with the DC power jack, seen directly to the right. I replaced the DC jack with a new one (as you might infer by the evidence of my sloppy workmanship) but unfortunately the problem with the indicated component remains.

So, I'm just wondering, what is that thing, what does it do, and can I repair or replace it. I'm hoping that I can just replace the solder and it will work again, but I'm not exactly holding my breath.

\$\endgroup\$

closed as off-topic by Leon Heller, Keelan, Daniel Grillo, Ricardo, Dave Tweed Oct 28 '14 at 10:48

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions on the repair of consumer electronics, appliances, or other devices must involve specific troubleshooting steps and demonstrate a good understanding of the underlying design of the device being repaired. See also: Is asking on how to fix a faulty circuit on topic?" – Leon Heller, Keelan, Daniel Grillo, Ricardo, Dave Tweed
If this question can be reworded to fit the rules in the help center, please edit the question.

  • 4
    \$\begingroup\$ I think it actually is a bead of solder, and your problem is elsewhere. \$\endgroup\$ – Ignacio Vazquez-Abrams Oct 28 '14 at 6:22
  • \$\begingroup\$ As @IgnacioVazquez-Abrams pointed out, it appears to be a solder bridge aka solder jumper: A blob of solder used to short two adjacent exposed pads on the PCB. The burn marks indicate that the solder blob is probably heating up due to the current through it. My first approach would be to replace the solder blob with lower resistance silver-based solder: Reduce the resistance of the "jumper", and it will generate less heat when passing current. Or, just use small bits of copper wire for the shunts. \$\endgroup\$ – Anindo Ghosh Oct 28 '14 at 6:34
  • \$\begingroup\$ It seems like it was always there though, so I suspect that something down the line is drawing an abnormally large amount of current and that this is just a symptom. \$\endgroup\$ – Ignacio Vazquez-Abrams Oct 28 '14 at 6:40
  • \$\begingroup\$ @Ignacio What about the fact that the burning was caused by the earlier DC jack issue, does that provide any clues? Also, everything seems to run fine off of the battery. If there is another problem further from the DC jack, I wouldn't know how to find it. \$\endgroup\$ – Matt Munson Oct 28 '14 at 6:48
  • 1
    \$\begingroup\$ I just want to say for the record that this question should NOT have been voted down as "off topic", so I'm "up" voting it. I've been repairing electronics for over 40 years, and there's still odd cases where like this that are pretty hard to identify both part and purpose. I DO wish the photo was more enlarged. Maybe it is just a "solder blob", but when and why would such a technique be used? In these days where you often can forget about obtaining a schematic without an "authorized repair center" license, it benefits everyone to have such mysteries shown and identified. \$\endgroup\$ – Randy Oct 29 '14 at 1:24