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Arlen Holder Arlen   Holder is offline
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Default Typical first pass tutorial process on Windows 10 where NONE of the extent how to articles actually tell you what you really need to do!

On Fri, 06 Nov 2020 14:11:00 -0500, Paul wrote:

I picked that particular chip because it's on *my* motherboard :-)


Oh. slaps head I was wondering why you had picked that chip!
o What I'm wondering is how the hell you knew it would be 48 pins square?

My Foxconn HRS880u-ATX has a bunch of 48-pin square 12x12 chips
o Where I marked each of them in a different color for you here
https://i.postimg.cc/JhhWnjTP/Foxconn-HRS880u-ATX.jpg

My orange U10 chip you fingered definitely says Realtek on it:
o But I think that's the Ethernet controller RTL911DL but I'm not sure
https://i.postimg.cc/ZKrmDbBF/48pinu10.jpg

Which, I think, may be this PCI Ethernet Controller chip:
http://www.image.micros.com.pl/_dane_techniczne_auto/uirtl8111dl.pdf

I would have an incentive to collect the sheet for it. I don't think
I have a very large collection of datasheets. Probably a few AC'97 ones
over the years.

One other thing that's interesting, is some chips have "muxes" for
Stereo_Mix but that one has a "summer", which is an entirely
different kettle of fish.

*******

c02431965.jpg

It took me roughly 3 seconds to spot it. Look for the green
dot in the lower left corner. A little bit down and to the right
a bit from that reference point, you'll find a 48 pin chip. The
chip will be square, and have 4 x 12 pins for a total of 48.
I can't see any detail though - look for a crab icon, the RealTek
icon, because they make a lot of these, all different classes
of audio. Everything from stereo to 7.1 .


I found the crab icon on my blue 48-pin 12x12 chip in the very corner.
o I think the number is ALC888S (with also date codes 97U19S1 G932C2).
https://i.postimg.cc/44HsVbX0/48pinu6.jpg

Which I think may be this sound controller chip:
https://www.hardwaresecrets.com/datasheets/ALC888S_DataSheet_1.2.pdf


HDAudio or AC'97 chips, usually have a pile of small electrolytics
used for AC coupling of signals.

There should also be a separate DC regulator, a linear, that
provides power to the chip. But it's pretty hard to clean
digital noise off a rail using a linear.

Sometimes in the PCB, you can see attempts to build
moats or put guard grounds around some of the analog
wiring. Or stick guards around the Ethernet wires,
so there is less coupling into the analog. There have been
lots of motherboards where total ignorance prevailed near
the 48 pin CODEC chip, and all sorts of mouse noises,
Ethernet noises and so on, ended up in the computer speakers.
It took quite a while for some of the motherboard companies
to become serious about the audio corner of the board.
I mean, in some cases, the interference was so bad, it
was obvious nobody ever lab-tested the audio. Or they
would not have let it ship. Motherboards are designed
three times total, with the third spin required
to be "patch wire free". Plenty of time to do an audio
test.

Paul


What I'm wondering is how the hell you knew it would be 48 pins square?