Today I was debugging a product with a membrane/keypad, I noticed that the contacts of the flat cable were black, ie not plated, I never saw this before, I am used to the FFC cables only
Is there any problem related with this kind of termination? I suppose is for lowering the price and, as it has a considerable resistance, it is possible to “carbonize” the contact and have a bigger resistance? if a high voltage is applied, like an ESD, because is what I see, high resistance if measured form the contact, and low if measured form the track itself (just before the contact)
Edit, when I said black, it was not shinny or bare metal look, cleaning with alcohol did not remove the black, but scrapping did it, so the ESD test did create that layer, I though it was a different kind (lower cost) termination.