CD Multichanger-The Sequel!

[snaefell]

I first posted on here in september 2017 when I could not get the cassette to eject on the multichanger on my newly aquired X350,a problem which seemed to sort itself & until lately has performed almost faultlessly,once or twice it has shown 'no discs' but has always seemed to right itself after popping the cassette in & out a couple of times).
But the other week while changing discs the message came up again & has remained,concerned that a disc may be stuck in the unit I removed the cassette,thankfully with all 6 discs,replacing the cassette,even with different discs has not cleared the problem,so what do you think guys,an early suggestion was that the laser may have gone,if so how difficult is the unit to replace for a numpty with 2 left hands(one of them with only half a thumb!!!).