Soldering onto a circuit board for the first time?

[Winny the pooh]

I'm modifying some LED strip lights that were hanging in my room to fit onto my quadcopter. They have an IR receiver so I can change them in the air which should be cool. Anyways, when I ripped the power port off the circuit board I couldn't tell which side was positive and negative and haven't been able to find any useful symbols on it to figure it out. Any ideas? I've circled the two connections that had been soldered.

Thanks!

 

[soggybottoms]

use the continuity mode on your voltmeter. you can see the 12v+ link. just need to verify and look for the -

 

[Bartman]

isn't that the 12v positive terminal in the upper right corner? If so, the trace on the board goes to the one spot you've circled so that would be the positive side.

and welcome to the site Winny, if I haven't said it already!

 

[Bartman]

it would help also if you could take a photo of the other side. the three pads labeled B, G, and R, are probably switched grounds allowing control of the light strings but seeing the other side (if the traces on the board are visible) would help.