My Marantz SR7400 remote control switches inputs by requiring you to press the input button twice within two seconds. For example, if I want to switch from DVD to TV I press the TV button twice. The Harmony One does not seem to able to support this action. Has anybody encountered this problem? If so, were you able to resolve it?

I've changed the delays but that does not seem to help and their tech support worked on it for about an hour and was not able to fix the problem either.

You can try to learn that command in Raw.
Give the button a new name.
In Raw you can give more commands together.
So you Push very quick the button twice.
Maybe it doesn't work the first time, so you have to play with it.

Did you try all the discrete input commands in device mode? Many devices support discrete commands even if they are not on the original remote. Also, your Marantz SR-7400 device default Adjust inputs configuration is set to use the discrete method (Method 2).

I have tried the commands in device mode. I use an IR sensor with my home theatre. If I use the harmony remote in device mode and point it directly at the AV receiver it switches inputs. If I use the IR sensor in the room and point it at the IR sensor doesn't work. I'm not sure if the IR sensor is impacting the input or not. I'll try to use the raw commands. Still no response from Logitech support. Thanks for responding.

1) I was asking if you Marantz SR7400 AVR supports discrete commands. Most AVRs support discrete commands even if they are not on the original remote. It's a lot easier with the discrete method (Method 2) than with the cycling method.

2) By IR sensor you mean IR repeater? If so, check the IR repeater option(s). Some have a sliding switch to select the IR frequency.

Logitech support was able to configure the remote correctly by sending two input signals to the AVR. Thank you again for responding.