I've been having issues with a MX-810 controlling a new marantz sr6003 through an RF extender, but it works fine with IR. The remote controls the sat box and the dvd player through RF fine, but not the receiver. The emitter is in the right place, and I've spent quite some time finely tuning the variable output on the MRF-260, but no luck. The emitter is blinking so I know its sending. Never had this problem before. Any suggestions that I haven't thought of would be great.

Have you tried switching emitters? Perhaps the emitter is faulty. Try using a different emitter port too. Did you check for RF interference using the ID #0 trick?

If your RF unit has an IR front-blaster (like what the MRF-260 or MRF-350), try holding the RF base unit in front of the Marantz amp and seeing if it works (you might have to enable the front blaster in the RF settings in the wizard). If that works, that proves your RF base unit is both receiving and re-transmitting the IR correctly, at least through the front blaster.

Are you using one of the variable ports? If not, you might be overpowering the sensor on the Marantz. Try one of the variable ports (1 or 2) and turn the output down all the way. If it doesn't work, slowly turn it up until it does (if it does).

Thanks. I'll check it out and get back to you. By the way, what is the ID 0 test? Is that just running it on channel 0 and see if it works? There is a Nuvo wireless ipod dock right next to it causing interference, so i'm going to try a different channel like 6 or 7. I'll get back to you.

ID #0 actually sniffs for RF interference. You can watch the busy light and if it's active, you have RFI. If not, you're fine.