Vintage Synth Repair

Hi everybody, I'm hoping some of you can help me out here, trying to repair a Juno 60.

whenever i switch the Juno on and play a 3 note melody with a long release, for example,start with A minor playing A,C,E,C    G,C,E,C  F,C,E,C  the last few notes are cutting each other off. 

If I play all the white notes up the keyboard one after the other, it plays fine. Always plays fine,until I play a melody again. 
So it doesn't seem to be the voice circuits. 

I also put the juno in the test mode and no funny note stealing or cutting off of releases happens.
but this mode is unusable as it plays a repeated note with a new voice causing phasing to occur.

Does anyone have any experience with this on a juno 60?
Or if you have a juno 60 could you try playing those notes after power on and see what happens, please?  Thank you. :-)