Sound issues on laptop (HW)

Support for any audio problems you may have. NOTE: Streaming issues, like silence or glitches, may be out of our control, as it is provided by a third party.
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shargo
Posts: 28
Joined: Thu Mar 05, 2020 4:56 pm
Location: Orust, Sweden

Sound issues on laptop (HW)

Post by shargo »

I have an old laptop (Toshiba Satellite L755D-115) that have some issues with sound. Normally I'd diagnose this myself and come to a rather confirmed conclusion but this acts rather strange to me.
After boot sound always seems to work but after a short time of usage it cuts off. I can let the laptop sit for a long time and sound works but after using it a minute or so it cuts. A few times I can get it back - for a minute or so.
The sound chip is a Intel High Definition Audio (aka "Azalia") but the laptop has speakers designed by Harman Kardon so I don't know if there might be some additional circuits by them.

This issue first appeared in Windows 7 but persisted when I switched it to Linux (current future use will most likely be Linux only) thus I'm sure it's hardware related.
It's an old machine at +10 years and was rather cheap back then (~500€) but it holds up well except for this and some failing plastics) and I also have a spare battery with double capacity.

If I use an external sound unit like bluetooth speakers it works fine.

So any ideas on how to get sound going?
I am pondering buying a cheap USB sound card and solder in that inside the laptop sacrificing an USB port but don't know (and doubt) it can drive the speakers. Or can I steal the audio from the external HDMI? (Is it analog audio and active without connected display?)

Additional HW info:
AMD Phenom™ II mobil processor med fyrdubbla kärnor P960
8 GB, DDR3 RAM (1 066 MHz)
AMD Radeon™ HD 6330M-grafik (2 GB dedicated V-RAM IIRC)
shargo
Posts: 28
Joined: Thu Mar 05, 2020 4:56 pm
Location: Orust, Sweden

Re: Sound issues on laptop (HW)

Post by shargo »

Additional info!

Just after posting I releasized I didn't remember if I had tested the audio via normal headphones so I started some music, waited for the sound to cut and plugged in the headphones and sound worked from them.
If I unplug them sound is still dead from the speakers.
Linux detects headphones plugged in or not correctly.

This really seems like an amplifier/sound treatment circuit fail and not the sound source circuits. Now, can I find schematics for this thing?
(Inputs on diagnosing and schematics still welcome.)
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zdooder
Posts: 27
Joined: Wed Mar 04, 2020 4:59 pm
Location: Phoenix, USA
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Re: Sound issues on laptop (HW)

Post by zdooder »

In my limited experience, "works for a bit then fails" usually means overheating. Maybe you could spray a can of compressed air or something to cool things down and see if that helps? (Could also help you "find" the amplifier circuit on the motherboard maybe?)
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shargo
Posts: 28
Joined: Thu Mar 05, 2020 4:56 pm
Location: Orust, Sweden

Re: Sound issues on laptop (HW)

Post by shargo »

Opened up the thing and remembered a couple of things. Headphone jack is in one corner and the speaker connector in the opposite and right between them is GPU and CPU and all the lanes to the screen port (nasty connector with a ton of long, tiny connectors). So no way for me to grasp which components might be related to audio by looking.
Normally the MB is protected from the metallic underside of the keyboard by a plastic film and the case so I hope it can boot with only an USB keyboard and mouse ignoring the lack of the built in ones (luckily it doesn't have the stupidity of a power button integrated in the keyboard).

In an (probably) unrelated knowledge about this laptop I had forgotten that I had added an extra heatsink to the VRAM :-)
(Four chips in total, the two on bottom of the board are covered by the same heatpipe as the GPU but nothing for the two on the top so I added a thin aluminium plate and cut out a part of the above mentioned plastic film. It used to get very hot in a single spot before but much better afterwards.)
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