Vintage Synth Repair

Hi!

I'm having problems with my stringmachines. Hopefully some of you 
have encountered similar problems and can help me out.

I just purchased a Solina String Ensemble which has a couple of 
problems. First of all, the keyboard action is terrible and some of 
the keys stick and will not bounce back up after pressing them down, 
but I think this can be easily fixed. The main drag is that the 
Crescendo (attack)-slider doesn't function at all. Or at least it 
doesn't do what it's supposed to.

When the Crescendo amount is adjusted to zero, everything works just 
fine; the sustain part of the envelope plays at normal volume and the 
Sustain (release) works just fine. When I start raising the Crescendo 
amount things start to go wrong; the envelope has no attack and the 
sustaining sound is just lowered in volume! When I set Crescendo to 
100% my Solina makes no sound at all! That is until I lift my fingers 
from the keyboard because the release still starts at maximum volume. 
I have no idea what could be causing this.

My Opus3 has also started showing signs of deterioration. The Brass 
and Organ sections work just fine, but the Strings section has some 
problems. The string sound starts crackling violently (sometimes 
there is just noise for a couple of sec) for no apparent reason. It 
can work normally for a week or so, but then it starts crackling 
again. And this happens on all three outputs. This problem usually 
disappears after some 10-15 minutes of playing, but sometimes it 
lasts for hours/days. The insides are clean and dustfree. What's 
wrong with it? Is it just dying?

I hope someone can help me with these problems, for these are my 
alltime favourite synths.

regards,

Matti Ikonen