I got a refurb 740 a few months back from A4L. It seemed to be new and in factory packaging with a QA slip marking it as "B-stock". It's connected to a TCL 55R615. It's mostly great, and it's actually fine for normal A/V use.
But I've been using REW to help with room configuration, speaker placement and so on. I've been connecting a laptop to the front panel HDMI input. I've been having a ton of trouble with that-- out of 5 input devices that I checked, only 3 work correctly and have multichannel audio. I don't think it's cable related, I've tried several and none of these devices will do more than 1080p60 anyway. (But I am on somewhat thin ice there, all my cables are either old, or generic "High Speed" HDMI cables supposedly used by DirectTV once upon a time.) Today I thought to try a rear input, and that works fine with all 5 devices. I know the front panel input is different/limited compared to the rear inputs, though Denon only says vaguely in the manual that 4K60 is limited to 4:2:0, rather than explicitly stating "HDMI 1.4" or the max pixel clock or anything else specific.
Devices that fail with the front panel input:
- a Dell Latitude 3150 running Windows 10 (computer switches to extended desktop, but usually nothing ever appears on the TV. If the display does work, the laptop only reports 2.0 HDMI audio)
- a Macbook Air with Accell Thunderbolt2-to-HDMI adapter (comes up at a very low resolution, like 640x480, and glitches/reinits every 5 seconds, not usable for anything)
Devices that work both places:
- the same Dell Latitude 3150, but running Linux (Ubuntu 19.04)
- an ancient Lenovo x120e running Windows 10
- Apple TV 4th generation
My first guess was some kind of hardware problem, either with a lot of cables, or with the front panel jack. But the Lenovo 3150 working differently with different OSes, along with some of the behavior I've seen, makes me think it's maybe a compatibility issue or bug with EDID or link setup or something. Has anyone seen similar behavior with this line of receivers?
And does anybody know of good tools/ways to debug HDMI issues in this sort of setup? I've sometimes looked at similar issues with computers and monitors but this is different. The Denon manual makes passing reference to "Custom" HDMI (EDID?) configuration that an integrator may have set. I suspect this is more about the higher-end models, is that configuration/information accessible on the 740? Are there any good tools for inspecting HDMI link configuration and EDIDs, for Windows/Linux?