I have a MacBook Pro Mid 2015 A1398 , I have the audio jack stuck in optical mode , I replaced the jack and now the stuck in optical mode is gone. The MacBook used to chime when powered on , but now does not.
But the sound still does not work from internal speaker or jack , if I connected Bluetooth headphones the sound works , if I plug a USB-Audio adapter the sound works.
I have checked the following :
Ok was checking voltages at C6600/C6601 = 3.3v and pin 10 audio jack same , then checked back to R6322 missing board revision / R6324/R6325/C6212 all 3.3v checked PP3V3_SO_AUDIO_ANALOG =3.3v checked C6302 =1.5v fed from U6200 checked pins 1-6 as follows 1=1.5v 2=0v 3=1.2v 4=3.3v 5=0v 6=4.9v pins 1 and 3 should be 4.5v , checked capacitor C6203 connected to pin 3 and both sides shorted so removed , need to check R6200 and C6200 I think it should be 4.5v and not 3.3v I think going to pin 4 u6200
Checked all components now L6201/C6213/C6214/C6212 = 3.3v
C6216/C6217/C6218/L6201 =0v should be 3.3v traced back to audio chip (u6201) and no vref should be 4.5v but output =0v does it mean the audio chip u6201 is faulty and need replacing or u6200 that powers the chip if I feed 4.5v direct to c6213 to put 4.5v there will it damage anything ???
I have found that the power chip U6200 is not output the correct 4.5v , traced back to Pin 10 of the sound chip and no voltage out.
Is it the Cirrus Logic power amp IC or some thing else, I can only find 1 fuse on the board are there any more.
Also no the display has failed when I was checking voltages back to the LCD connector 5v feed.
It is a A1398 , 820-00138-A logic board MBP Mid 2015.
Any help would be great
