lock indicator stays on ok!! please help


john pick

first time on this site and it looks like if anyone can help me its you guys!
my dish was knocked out of line and i easily moved it back so that the lock indicator switched from not locked to ok. all was fine up untill my flat mate decided to hang his washing on the main bracket arm (nice!!). thought there would be no problems id just do the same as before, but now even when i reset the box by unplugging the mains for 30 seconds the lock indicator stays on ok even when the lnb is unplugged!?!?. i just cant get my head around this? so called out the installer he says the dish is aligned and working fine buy a new box! this is not an option as a new box is €445 (if you catch my drift lol)