I'm out in the field and can't seem to download the PDF from Denons site.
What does the blinking red power light mean? Had customer unplug avr then plug in. Same thing, comes up blinking red. She turns off then on. Unit goes green power light briefly then turn red blinking?
Googled it and couldn't find a definitive answer. Just trying get info before driving to site.
TIA

1 Turn off the power using power button.
2 Press power button while simultaneously pressing TUNER PRESET
CH – and TUNER PRESET CH +.
3 Once the display starts flashing at intervals of about 1
second, release the two buttons.

** this will reset all settings **

You may have a shorted speaker wire in the mix...

If it doesn't reset then remove the speaker wires and try to turn on.

If thats the case you may have a shorted amp.

do a microprocessor reset on the unit

Resetting means that anything you have programmed, such as an input's audio mode or a digital input connected with non-default video input, will require a service trip. Think that through before you call so you can warn the client that you might be able to avoid a service trip, you can't guarantee it, but it's worth a try.

I wonder if the blinking red light might indicate a shorted output or other power amp problem.

Sounds like a Denon Amp. I've had a few go into repair for things like this - some coming back "fixed" then back to the problem again.

This used to mean the protection circuit has been "used" and a quick $125 trip to the repair shop (out of warranty if course) was the fix. But I have not touched a denon AVR for several years. Last one I remember bricked itself while trying to do an update. Twice. I cannot remember if the red light flashed or not.

First, turn off the speakers or disconnect the speaker wires- if it turns on this way, the speakers or wires have a problem. If they have a cat or small dog, look for signs of chewing on the wires.

Why was the power wire unplugged?

I had the customer unplug and replug it while I was on the phone with her to see if that would clear it up.
Speaker short or clipping came to mind but it's a new install (month old) with ceiling speakers. I guess I'll see when I get there......

Typically it's related to a speaker short or impedance problem.

Also, check the volume level - If she has the volume up at full, it may not turn on and is protecting itself.

Here's an insidious problem: Check to see if zone 2 volume is up full. This can be amazingly hard to locate if the receiver turns on with, say, Zone 2 on tuner, not on automatic, and Zone 2 volume up all the way. FM interstation noise at full volume can shut down a receiver or keep it from starting.

The cure would be resetting the receiver in hopes that a reset takes it off Zone 2 tuner. If it stays on after the reset, check Zone 2 to be sure it's not on Tuner and that its volume is at a reasonable level.

Since some Denon remotes make you cycle through zone 2 control after you control the tuner, the unwitting user may switch out of tuner, into zone 2, turn up the volume on non-existent speakers, realize that something's wrong, then switch to the main zone without realizing they've turned zone 2 up all the way.

She said she'd be watching TV and it would just go out and the Sammy TV would show HDMI 1- with no pic. She'd turn everything off via remote and then turn it back on. This worked for "a few times" according to her. She called Verizon before be and they had her go through various things and "determined" the "special cable" is bad. Your audio installer should know which one.
Heading there tomorrow to see what's up. Hopefully it's not the Denon!!!

Keep us posted.

If it follows Marantz it is in protect mode. I would unplug everything and see if it powers back up. If not it needs to be repaired.

Disconnected all speakers, still blinking.... Unplugged the 2 input HDMI's , 1 monitor HDMI, 1 digital coax from Sonos, 1 ir in from control system. Still blinking.....bad amp according to manual.
Are you guys having any issues with the current Denon's? I have to check but this unit has only been in for about two months, max.

But did you do the reset?