Display The display screen on my STR-DE715 receiver does not light up.  Is there a way to reset the system to activate the display.? thank you

Does the rest of the receiver work? Do you get audio output? If not, it could be the main power transformer. There is a thermal fuse buried in the core that if this opens, it will cause the unit to not power up completely.

Might be short circuit protection or over load protection activated. Contact any service technician, to confirm what the reason is. If you wish to get some details; check the site linked here. Viewing it in "Mosaic" or "Magazine" will make surf easy. Pull up older posts. Surf the site with patience. Do a search by type in the brand name of your device at its search box and press "Enter".
http://electronicshelponline.blogspot.com/

there are a number of possibilities, bad solder connections on the display board, missing B+, a defective driver display ic, this is a situation a diagram would be helpfull.

I believe what you want to do is as follows. Turn off the power supply. Hold the buttons 6, 7, 8. And turn on the power. The display should activate all options, then turn on and off a few times and finally display End. Then the memory should be reset back to Factory.

For the STR-DG800 you need to power off. Then hold power button 5 seconds. When "push entrer" appears on display push "memory/enter" button. System will turn off and reset.

The audio amplifier IC are damaged and need to be replaced

I couldn't find anything about a Lock Code in the manual but here's the general setting-reset procedure:

Turn OFF the receiver
Hold down the I/0 for 5 seconds - "PUSH ENTER" appears on the display
Press ENTER

3.2 IS the "5.1" mode for this receiver. 3.2 is indicating that you have 3 front channels and 2 rear channels. The ".1" is applied to all the speakers (LFE). If you read the manual on page 37, you'll see that "3.2" is displayed with either "Dolby Digital 3.2" or "DTS 3.2". The little icons of the speakers in the display window will show you which channels are active. The bottom line is as long as you see the blue light, it's decoding multi-channel discreet surround sound (at least 5.1).

If this is a recent occurrence, unplug receiver for 20 minutes. This will reset the receiver. If the remote is programmable, reprogram it for the receiver. If you do these steps and it does not work, you need a different remote.

I have the same problem, i also have a STR-DE715. I have two thunder acoustic speakers and two 12in. punch subs. Now when i only play the subs i can go max volume, no problem, great bass the whole deal. Then when i play the thunder speakers i cant even go half way without the receiver shutting off and saying "protector" on the screen(both the speakers are 120 watt). From personal experience i think it could be the speakers youre using, either the receiver is giving too much juice and its preventing the speakers from blowing or the speakers need more power and the receiver cant give it. So a new set of speaker might be what you need. The receiver is 280 watts so something in that zone should work out. Also try turning off the sound field if you're using more than two speakers for the front output (i read this in the manual, you can pull up the users manual on www.manualshark.org and see if you can find something i might've missed) it supposed tp help it in one way or another. E-mail me at [email protected] and tell me if your problem was fixed or not. Im pretty curious myself to find a solution to this problem. hope this helps!