I have the problem that realtek device random disappear from Windows device list and no audio is emitted, the sound icon have a red X with message "no output audio devices are installed".
This problem append to me from september/october 2017, first one time at week and recently almost one time on every two days. I've ever solved with various dell realtek driver installations and various reboot but from yesterday I can't be able to restore the device.
In the BIOS, at "System information" there is writed: "Audio controller =(none)", the diagnostics tests pass without errors but no beep is emitted.
I don't know anymore what I can do, I've tried all procedures that I've read in another threads
I've open a support ticket a couple of minutes ago (I've last two weeks of warrantly).
About that "Audio controller = (none)" line item in diagnostics: Does "None" in that context mean "No errors" or does it mean "No device"? Based on the wording, the lack of beeps during the test, and the Device Manager behavior, I'm guessing it means the latter. In that case, no amount of driver updates or special driver installation sequences is going to resolve this. If drivers were the issue, then you would still see SOMETHING in Device Manager, either an unknown device or at least an error icon on the Realtek device. But if the Realtek device has disappeared and you don't see any other unknown devices in its place, then it sounds like something on the motherboard has failed in a way that rendered the audio controller unusable, in which case you'd need a motherboard replacement.
If the problem is intermittent, I guess it could be a short of some kind on the board. You could open your system up to make sure you don't have a screw or some other piece of metal loose in there that might be causing that, but unless it's something obvious like that, then this is going to be a hardware replacement issue. The audio controller is soldered directly onto the motherboard, so this wouldn't be a loose cable issue. Even if the speaker connectors were loose, the audio device itself would still appear.
Thank you for answer jphughan, you've caught in the sign.
Yes the "none" was in the system information where devices are listed so it means "no device".
At first I've thought at a driver problem caused maybe by windows updates but when the frequency of the problem has increased I've started to suspect a hardware problem.
When Realtek device disappear, there are no others unknown devices.
The cable test pass also without errors (why there is not a dedicated test for sound card?)
I hope that support understand.
Update: device returned as previous happened, and I have the sound.
In the bios screen now in audio controller instead of "none" there is "ALC3266", the diagnostics emit the beeps and device is showed in his place in device manager.
Now it's question of time to the next problem occurs.
I'll wait the answer of the support.
Update 2: audio gone
Still no answer from support.
Could this problem be related at the battery swelling that afflict the 9550 series?
My battery have only 35 cycles and the trackpad seems ok but today I had a strange episode: while I was listening music, it stops suddently and this time the Realtek device was there, so there was another problem.
When I put the weight of my hands on the chassis to write, the sound returned and when I removed the hands again no sounds, so I made a slight pressure and sounds was permmanently reproduced (until now).
It's a strange thing, never appened.
I previously had a battery problem that for now I solved with calibration but battery have 82% of health and 69/86 mWh of capacity with only 35 cycles in almost a year. For the support is normal.
The page for battery replace reported this: "If your battery is not swollen, please use the process below to request a replacement battery."
But in request page I can't continue because "Only units with Action Recommended / Required qualify to be processed" and my have "no action required".
UPDATE: Yes I can confirm that this second problem occurs based on how the chassis is pressed and handled