korg ms-20 problems

[omaroski]

hi to all!
i recently bought a korg ms-20 at a fairly good price, it was my first time on a synth,
so i'm learning and i'm not so experienced! I would like to bring it to the tech if needed but
would like to learn first what is happening in it!
so let's start, here are different problems (?), always born after trying to patching:
-the ''release'' doesn't work if it is set less than about 1, it means no sound on the output
-the ''hold'' doesn't work or it works only when i play a lot of legato notes
-both the ''attack'' and ''decay'' do not work like i guess they should
-generally i can't get sounds with a percussion attack if i set the ''sustain'' low
-sometimes the oscillators are not in tune
please help me to figure out what is going on and if i need the tech
thank you
Omar