Boy, I take an hour to run errands and you wrap yourself around the axle.
Hmmmm (thinking cap on). First of all, the MX-700 commands in the file I provided aren't new or old, they are the codes that Denon uses for all of their receivers. I'm not having issues with them on my 3803, so you shouldn't either. Also - clearly, what you are describing is not a cabling/connection issue since it only happens when you fool around with the 700 file.
Where does that leave us? The 3803 & 3805 have a Mode function and that allows the receiver to do all the sensing and reporting you describe as the sources change. I have mine set an Auto, it sounds like you have yours set on Auto as well, until you do something to change it, probably via the remote.
Here's the bad news - you will need to get into the manual to resolve this. Start with looking for the information on the Auto Mode setting and see if you can get it reset using the Denon remote or the controls on the face of the 3805. I believe it will be a simple turn of a knob or command from the 3805 remote. It really should be that simple. Also, take a look at the section of the manual titled "Troubleshooting".
Next, understand the risk of simply using the file/commands I sent you. I know what they are for and what the labels mean. Since you haven't spent any meaningful time in the MX-700 programming manual or the Denon manual, you may be making some assumptions about the commands/labels in the 700 file I sent and shooting yourself in the foot.
If I were you, I would use the 3805 remote for the time being. When you finally sit down and focus on the 700 and it's documentation, you can build a file for the 3805 specific to your personal needs. The David Gray file I sent you will support that easily and I will be happy to help you.
Finally, both the 3805 and MX-700 are feature-rich and powerful pieces of equipment with considerable detail to understand. You should really set aside the time to master these guys - they are at the core of your entire HT setup. Plus, you'll be a walking electro wizard.
Let me know how the thing progresses.
