Actually I tested the PM981 as well and it shows the same issues. I would recommend the PM961 as I have installed multiple of these in any Imac of the 2015/2017/2019 year and they work perfectly. And they are cheaper as well than the PM981. Here in Europe these PM961’s sell for around EUR 100,- a piece.
Actually this answer is incorrect. As of the 2017 model(so includes 2019 models), it’s as follows: The Isight camera is still located as mentioned at the top of the display. The microphone and cable are located at the bottom of the Imac, about 1/3rd from the right. It’s connected with a tiny flatcable to the logic board.
Hi, I have a similar problem with 3 different boards: (1) 2 ea 820-00292 Imac 5K 2015 boards (2) 1 Imac 21.5” 3.0Ghz GPU-555 2017 board All 3 have no LED at all. Checked voltage from PSU and it’s 12V OK Tried 3 different PSU’s and all the same, and the PSU’s work with a normal board. SO ruled out PSU. Checked voltage on first LED and 0.5V. So some short in the trickle power circuit? Any suggestions appreciated. Am a newby on board level repairs but am interested to learn. Thanks, Ron