Hi Nico
I have chipped several USAtrains locos of different types,
I found from experience that it is quite easy to do, BUT it is best in my opinion to forget any pre fitted PCBs and simply wire everything, lights, LED markers smoke units etc directly to the decoder outputs,
I beleive but not 100% sure that the QSI decoder adaptor has screw connectors?
Ask Jeremy he sell them so will know.
One thing to be aware of with USAt locos is that some of the soldered connections are quite fragile especially around the bogie area where lots of movement occurs, So check them frequently,
Also access to the innards usualy requires a long thin cross headed screwdriver to access the retaining screws for the body, and a little fiddling is required to access some of these, especially the nose end of the F3 A units!!
I fitted mostly ESU loksound decoders and could usuually do a loco in an afternoon!!
