Dear All,
Got invited by someone who lives quite near me to come and have a look at his Mellotron as (I quote)"bought in 1975 and haven't powered it up since 1982".
Thankfully all this time had been spent indoors in a reasonable atmosphere so the major problems were dirt and the tapes being set in a permanent W shape. A number of pre-flight checks were carried out, plus some cleaning, tightening and de-magging the beast was powered up and after the usual CMC10 pause it fired up as keen as you like. With a set of my tapes in it played really well - much to my surprise!
Result - one of the tidiest M400's I've ever seen back in action...
Norm