Hello Every One ,

This is Redmi Note 9 mobile. This mobile came from another shop near us.This mobile came to us with touch problem.Another technician removed the cpu and reballed it. But the problem was not solved. Now let's solve the problem in this mobile.

Now   let's   check   this   mobile :

Krish Mobile Training Institute

• First we need to open the mobile back panel.
• The Mother Board should be separated from the mobile.
• First check the Gr value above the touch lines of the display connector.

If you want to Know More Information then Click on this Link :-www.youtube.com/@krishmobiletraininginstitute.

• Here the TP SPI MISO line is missed.
• Gr value is missing on the 4th pin above the display connector touch lines. It says OL.
• That line is the TP SPI MISO line.

• this TP SPI MISO line comes from cpu.
• Another technician already checked this line and noticed that the line was coming from the cpu and reballed the cpu.
• Here we have done a trick.
• Remove the CPU and check if there is connectivity from the CPU touchpad to the display connector.
• Another technician did not check this.
• That line is cut internally. If the connectivity is good, if the cpu reball and refix, the problem will be solved.
• Over all, the TP SPI MISO line is missing.

Now let's solve the problem in this mobile :

• Remove the cpu and clean the cpu pad with a wick.
• Connectivity should be check with multimeter with the help of a jumper from the Display connector to the cpu pad.
• On checking, it was found that the line was cut.
• So now we need to put a micro jumper from the pad under the cpu to the display connector.

• Now we have to downgrade and clean cpu.
• cpu should be reballed after cleaning.
• After thinking that the Reball is correct, the cpu should look at the direction one and refix.
• Check the value of Gr on the 4th pin once.

• Then attach the mother board to your mobile.
• Check if the mobile turns on or not.
• Mobile turned on successfully.
• Check if the Touch is working or not.
• Touch will work.
• problem is solved .
• customer is happy.

video link is given in the below :

thank you by team k.m.t