JX-3P one out of the 6 voices is dead

Since it is a 6 voice, it seems as I play it randomly kill a note- so I assume one of the voice of the 6 is dead. It does not do it on all the patches - So I am guessing it is related to the square wave since the Oboe sound misses the 6th note I play.
Which part will I need to buy from Syntaur to fix the problem?
I will update this post once I run the diagnostics.

I tested it and it is the Squarewave on first voice that does not play.
In diagnostics, it cycles between the 6 voices showing as patch select 11 through 16. It is patch 11 that lights but no voice. So I am concluding that would be the first voice.
What parts I need to buy?

Ok looking at the schematics, I will need the IC 4011.
I was hoping for some feedback…but it seems not.

We do have the 4011 chip available:

Your issue is really difficult to diagnose remotely - without having the keyboard available for poking and prodding on, there’s no way to make an assessment of which of the many components in a voice circuit is failing.