I was attempting to drive the PSR 3000 from my computer Power Tracks Pro 9) and chaining a Yamaha RX21 for a click track. The Yamaha also does not have a thru on it, however I found out that the Yamaha's out defaults as a thru so I just put it first in the chain and it works fine. Thanks for the suggestions. I am still curious as to whether I can thru enable the 3000.