Display goes out after 15-30 seconds...

http://www.fixya.com/support/t5532415-denon

Suggested by someone else

Try that

No this unit does not support HDMI I downloaded the 3805 manual at http://usa.denon.com/US/Downloads/Pages/InstructionManual.aspx

page 100 list the three types of video connectios

In other words you need the manuals...

http://usa.denon.com/us/downloads/pages/instructionmanual.aspx

Check "search by text" and enter "avr3805"

SW means sub woofer, not necessary means center speaker in all receivers. Instead of setting 5ch stereo, if you have 3 speakers. try to set "3channel" or "simulated". If you own more than 3 speakers, you may refer to the user´s manual to correctly wire them to get the full sound.

No, you would be better off sending the video signal from your sources(satellite,digital cable,DVD,BluRay player,any digital HD source,etc.)directly to your Samsung TV, and then use the fiber optic output from the TV to transfer the audio signal to your Denon receiver, or another way is to send all video signal to your TV and send all audio signal to your Denon receiver seperately, keep in mind that there really isn't a good reason to send video into a Denon receiver, that processes sound not picture! Good Luck !

There is a button on the front of the unit under Input its a mode button press this button to select auto that should give you sound

http://www.usa.denon.com/ArchivedAVReceivers.asp?archivedModelSearch=true&clearCurrent=true&archivedCategory=AV&archivedModel=AVR-3805&imageField.x=10&imageField.y=9

cut and paste the link.
All the info you need should be there

try a hardware reset based on instruction under
http://www.fixya.com/support/t701165-denon_avr_3805_video_problem

If you have checked thru the owners manual and could not find anything helpful for getting the OSD working again, you may want to try this reset procedure at the end of this post and then try to get the OSD working again. The owners manual should give instructions on how to activate the OSD.

This reset procedure will clear all the setting you have made, so make sure you know how to put those settings back in again before doing this.

If you do see the video from what ever video device you have connected to the unit (DVD player ect. ) but you don't see the OSD when you enter into any setup menu, then this reset procedure may help fix that problem.

If you are not seeing any video from the video device connected to the unit, then you may just have the wrong setting for the output from the video out to the TV. These Denon's are very complicated receivers (which you must know, since you own this receiver), and an improper setting can be causing the problems you have.

Befor eyou do this, go thru the settings menu and look for a OSD setting and see if it is turned off. If so, turn it on. If you can not find anything for the OSD try using the set up on the display of the Denon instead of the remote.

Here is the reset procedure:

With the unit turned off, hold down these two buttons at the same time:

Pure direct + Direct

while holding those buttons down, then press the power button to turn on the unit. Keep holding those buttons down for at least 3 seconds after turing the unit on and the display should flash at about 1 second intervals. then you can let off the two buttons and the unit is reset back to the same settings as when it was new. You now will need to put all of your custom settings back in to the way you need them.

It's likely that you have shorted some speaker outputs, I had that problem and sorted it. Unfortunately it does mean replacing some output transistors..the devices are dificult to get to just to add insult to injury. They are the devices that are mounted directly onto the large heatsink and solder connected to the bottom circuit board. You only have to change the matched pair that you have blown....tricky to identify which ones without some electronics knowledge. The power output section does have some fuses to protect it but sadly these do not appear to be fast enough to stop "one" from damaging the power output stage if you unfortunately short outputs. The transistors are available from Farnell, use pin compatible replacements SAP15N and SAP15P.....all the best. Doctor Bill