power off
remove the lid by removing screws at the top rear of machine slide the top rearwards then lift off
find the bottom of the soap drawer and remove the large feed pipe that gos to the drum do the same at the other end where it is attached to the outer drum clean out the caked power and then refit pipe, try a fill and test for leaks if OK then refit the top
(you could always put the powder into the drum in a ball)
wirecutterman, January 2011