ModWright Transporter right channel question...

One thing you might check is a loose rca jack. My left channel just quit the other day. When I went to switch interconnects to rule the cables out, I noticed the left channel jack was rotating freely. I popped the cover off the unit - a PITA - and lo and behold, the jack had rotated such that a tiny resistor had broken free of its solder joint.

I'll be calling Dan soon myself...

It could be any number of things. I would suspect a bad cap somewhere in the output circuit. Before trying anything, give Dan Wright a call or an email and ask him. Dan is very responsive and is willing to offer some self-diagnosis tips for you to try.