Hello everyone, I'm having audio issues. When the laptop boots into windows, there is a loud whining noise from the two front main speakers (only happens when in windows). I replaced both smart audio amplifier chips (TFA9891) but the problem remains the same.Bios updates and various drivers have not helped (default windows drivers only activates the two small speakers above the keyboard and those are OK) .So I decided to replace the audio codec (CX9602-11Z) with a brand new chip but surprisingly, the PC does not detect any audio device, but when I revert back to the old chip, audio is detected and I don't understand because the new chip was perfectly placed on the board and part number is same. I want to know if something has to be done when a new codec is installed or whether the new chip is faulty? (all chips bought from supplier always worked). Any help will be appreciated.

"New" codec may be defective. At first check codec power supply with oscilloscope and all points from amplifier outputs to speakers, then try few another codecs.

Thanks for reply. luckly I bought 2 chips so will solder 2nd chip and see. Checking pinouts on codec is going to be impossible due to the fact that schematic is unavailable and I've searched in vain for a datasheet. I will be very grateful if someone can point me to a schematic with codec CX9602-11Z.