https://sites.google.com/site/korgdemo/roland/motherboard
Check out the audio file Voice0006.amr
I have recorded the fault, there may be some background noise because I used my phone but you should still be able to clearly hear what is going on.
Each note played is only one press of a key then you will hear it repeat.
It is not the effects doing this because it happens with all effects turned off.

 

well that certainly isn't noise, but surely is an affect. In your opinion, if you wanted to recreate that condition on a working board, how would you do it?.

 

I would add delay with a touch if feedback.
I should record it with no effect on which might give you a better idea.
I Think pulsing is the word I am looking for when I am trying to describe what is going on.