It's definfinatly internal as it appears on the headphone out of the JV-1080.
It's also a regular click as it's effected by changing the Reverb type. If the reverb is turned off the click goes.
Chorus and Delay seem uneffected (no pun intended).

The owner of the 1080 is going to call Roland tomorrow, hopefully they might know what it is.

Thanks for your input...