Mellotronists

Hi... 

I need some help with my mellotron. She is not working properly. I have
had it in a warehouse for 1 year (I have to move to another place and I
had no place to keep the 'tron until now). After that year I moved the
mellotron here by my own, in a van, on its case and with care. When it
arrived, the tron sounded terribly out of tune and oscillating in a
whoaaa-whoa---wahwah.... I was so scared, but after changing it in the
room and waiting some days, it appears to work properly, except that:

1. sometimes (specially when I change the sounds) the engine goes faster
and starts to oscillate and then the tune goes off in a wah wah.

2. now when I push 3 or more lower keys, the sound after 2 or 3 seconds
starts to oscillate too like fading and the engine seems to oscillate
too. I don't think it is an issue on the tapes because it behaves
similarly on every sound.

I beg your help on this.

Thanks a lot.

Sincerely.

Nacho.