119W comes in on the east feed horn and 103W comes in on the west feed horn (along with 101W and 99W). The middle feed horn is for 110W. The dish is a reflector so whatever is up in the sky is going to be reversed after it hits the dish (west becomes east and vice versa).
The fact that you can get 101W and 99W without much trouble suggests that aiming isn't the source of your zero signal problem with 103W. Worst case would be that 119W wouldn't be optimal but your 110W signal strength indicates that's probably not the case.
Again, it sounds like a switchgear issue; probably related to heat.