The solution below works for Tecno K7 mic or mouthpiece not working. Either it just didn't work even after changing the down board or charging port panel, or you discovered it stopped working after changing the complete screen.
The problem may be due to bad connection in the LCD screen, instead of wasting another money to buy a new screen, check out the solution below, it solves the problem 100%.
This also is a solution for speaker not working even after changing the speaker / ringer and the down board / charging port panel.
Trace the broken link and apply jumper, Enjoy.
Tecno K7 mic / mouth piece not working
Tecno K7 mic speaker / ringer not working
Tecno K7 charging port not working