Hi. I have got exactly same problem with my harman kardon sabre sb35 soundbar. The remote does not switch it on or does not control the voulme. Only power off works well. What i worked out is that once you press and hold power off button to reboot tv then it trigger soundbar on and that is the only way. I think it has something to do with tv going to stand by mode when you press power off. Try to press and hold power button. I guess that will power the amplifier on.
