TCL LCD TV Samsung screen ghosting fault change logic board chip process - android - Phones Developers

Electronic scale crystal oscillator 3.2*2.5mm 3225 16M (16.000MHZ) 12PF 10PPM 20PPM 30PPM

Brand AVX TPSE226M035R0125 Low impedance tantalum capacitor AVX 22

SMD aluminum electrolytic capacitor

MOS power IC full range

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

Fault phenomenon: TCL Samsung logic board one screen ghost!
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Maintenance process: First brush the data once, the fault remains. Can only change the chip to try luck, knowing that the success rate is almost 0.
From which one? It’s difficult to start with the first one. It starts with the pin and starts to adjust to 340 degrees with a hot air gun.
Slowly move around the tuyere and heat it evenly (only one person can't do it, can't take the process) and remove it with tweezers.

Align the four sides of the foot, first fix a pin with tin, fix the four pins, and finally fill the tin to prepare for drag welding.

It is best to use a constant temperature soldering iron for drag welding. If the temperature is high, the board will be easily soldered.

The welding is completed, the power is tested, the fault remains, the most likely chip is eliminated, and the mood is lost...

Adjust your mindset, prepare to change your feet, choose a small one, I haven’t soldered this chip for a long time, let him practice it first.
Apply a little solder paste around and remove it with a heat gun.

Clean the circuit board, drag the pad flat, and then drag the new chip around the tin to avoid excessive soldering.
It is easy to weld, then apply a solder paste on the pad, and the chip is also coated around. The solder paste is a little sticky.
Put the chip on the pad, align it, and heat it evenly with the air gun. The air volume is not too big, it is smaller than when the chip is taken.
It is not necessary to blow the chip away. When the tin is melted, the chip will sink. When the chip is gently pulled down with a tweezers, it will automatically return to the position, and the welding is OK!

Observing no short-circuit or air-welding around, the solder pads of each pad are full, and the test machine is energized, and the heart is hit again.

The lucky god still did not come to patronize, only the last big power chip, the voltage of each road was tested, no abnormalities were found.
It can be said that the repair is hopeless, and can only wait for a miracle!
The power chip is also devoid of feet, and the solder paste is heated and removed.

As usual, cleaning the circuit board, padding flat, chip tin, circuit board, chip coating solder paste, alignment heating, soldering OK!

I really want to invite Liu Qian to here, let him come to witness the moment of miracles, but unfortunately I don’t know Liu Qian’s phone, and I have not witnessed the miracle.
The headquarters began to pronounce: TCL L40P60FBD Samsung screen LTA400HM14 sentenced to life imprisonment, hope to turn another complaint!
Thank you for your guidance, let you see so much nonsense, apologize!