This is a popular question and the answer is no.  It is not possible to precisely diagnose your unit with out taking the lid off or not even seeing it.

If it is something we have seen before we may be able to give you a guide, but to be precise over the phone is guess work.

Forums can be informative, however , they are mostly written by people that do not have all the facts and knowledge about the topic. Non certified technical experts,  Don't be convinced that what you are reading is always the truth.

Unfortunatley, as we have come to find out from our customer feed back " If it's on the internet, it must be true !"