Vintage Synth Repair

Hi guys,

In my Juno106 there's always an audio signal on the audio_out port 
that is faintly audible, but strong enough to the point that it's 
intorelable during a recording. In order to get rid of it I need to 
switch off the generators - DCO sawwave, DCO pulsewave, subosc - 
depending on what is employed in a given patch. But then, of course, 
I cannot play. The signal changes pitch if I press several keys. I 
mean - now I hear C1. But I just need to press several different keys 
in another octave, lets say in the last tone, and then the signal 
changes into e.g E5. Basically the note played by the synth itself is 
the last note/key I struck. 

Some guy says this: "You have a defective 80017a voice chip that 
doesn't shut off its VCA when that voice is played. You can get a 
replacement chip at www.synthparts.com". Is it really so?

I can tell you that the 106 has been on for the entire day today and 
nothing chages, this signal/voice just keeps on sounding. But does it 
mean that along with time the chip's condition is going to 
deteriorate and finally it'll start to lose the voice ?

If so, may I buy a new chip from this guy?
http://users.skynet.be/bk318113/303/juno.html
It's cheaper and new.

Of course I would neeed a service manual for Juno106.
Waiting for your help.

cheers