if its a desktop for example, or a home use printer... yes its worth it just to change the printer, or the broken component... but when it's a laptop that costs 1000 euro, and a new "component" will cost you 400... is that worth it? or is it worth it to repair it for 100, thats what i meant... because the 400 you are going to pay for the board is... well lets just say close to the amount the reseller is going to pay for it.
And the part with the oscilloscope, lets just say that now there is no more time for viewing signals to see if the chip is working properly, you have to move fast, you have to know what you are looking for, the osc is a great tool, when you have time to use it
and the methodology is kinda the same believe me...
If your laptop broke... what would you do? scrap it and buy another one? And i'm not talking about a hard-drive failing or your processor breaking... i'm talking about defects that need motherboard level intervention... would you be happy paying the price of another motherboard... or just paying for it to be fixed? You as a customer...