Have just come across an old Soundcraft LM1 mixer that I'd like to dust down and get working properly again. If anyone is familiar with this mixer i'd like to know how to adjust the 1khz tone generator level so it hits 4ppm/0dbu when the master L-R is up to 0. At the moment tone is lining up between 4.5-6PPM when I'm adjusting the needle sensitivity with a tweaker (doesn't go any lower). Thanks in advance!