I have a radioshack 45 watt desoldering iron, and it wont work correctly on the pc boards out of a sony television, it will melt and suck up some of the solder, but not all of it so I can't get the parts such and sockets and such out correctly. However it works perfectly on a pc boards out of things such as power supplies. It wouldnt even work right after i put a brand new tip on it. Any ideas? thanks in advance.