Question Yamaha receiver only detecting 2 audio channels ?


Nov 9, 2016
Hello all,

Recently I purchased a klipsch 5.1 surround system, and a receiver able to go along with it (bought used). It is a Yamaha RX-V663. For the first week and a half it has worked perfectly, not a single issue. It is plugged into my PC, through the HDMI passthrough, into a secondary 1080p 60hz monitor, nothing special. Surround audio worked perfectly, all 5 speakers (and sub) registered independently when I played a test tone. Another thing I don't know if it matters or not, but I power off the receiver every night.

I woke up one morning and it just wouldn't play any sound, the PCM light was on which means it's detecting 2ch audio, and only the L and R speakers are lit up. I spent an hour trying to figure out what the issue was, and finally rebooted my computer, after rebooting, it worked perfectly normal, all 5 speakers played their tones independently, surround worked in the game, all was good.

Woke up today, and it was doing the same thing, but now the tones are coming out of all the different speakers, but the surround back speakers tones also come out on the front L/R speakers, and the L/R sound comes out of the left/Right of the center channel. I'm honestly very confused as to the entire issue. Receiver has definitely not overheated, I have 2 exhaust fans on the top pulling air though (temperature checked with a temp gun as well), so I'm wondering if it is an issue with a nvidia driver of some sort, or a windows driver. Any help would be greatly appreciated.

update: Restarted my PC again, and surround is fully working again. If anyone has advice on what I can do to not have to restart my computer every time I want to listen to anything, that would be great.

second update: pcm light came back on, now it is playing in only 2-channel audio again, but through all speakers..

Thanks in advance!
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An intermittent problem such as you describe suggests to me that there is a loose connection somewhere.

Double check all connections (plugs and ports) to ensure that they are fully and firmly in place.

Ensure that none of the audio cables (or any other cables for that matter) are kinked, crushed, stretched, or showing some sign of physical damage. Fore example, bare conductor showing, cuts in insulation, smashed sections.

Otherwise, look for some pattern in the failures. Become aware of how you shutdown and restart.

Not only your computer but other devices as well.

Also, on your computer, open Reliability History.

Look for error codes, warnings, and even informational events that correspond (timeline) with the surround audio failures.