Quote: Originally Posted by
tempgp 
what makes u 100% sure that those components are missing?
In the Q21 there are some missing pieces of the component in the solder in the bottom right pin. And all the solder pins look like there has been something on them. The pins doesn't look chubby like unused ones, they look coarse and flat.
Quote: Originally Posted by
tempgp 
i dont think robot forgot to solder in a resistor and diode bridge
I think that the previous owner of the board was sloppy and knocked the board onto his case.