This is a Samsung A10.Our client had its display replaced, and it never powered on. Let’s check it out.
Power on, no response.
USB connected, see if there is any current. Only 0.05A.
Disconnect USB, turn it around. Disconnect the battery cable. Get it to the main power, check out its current. Electricity-leakage happens on the logic board, 40mA.
Basically, some circuit has cut-off.
Disconnect the power cable, the display cable, charging cable and the power-on cable. Remove the logic board. Next we are going to measure the diode reading around the display-related circuits and see if there is any problem.
Measure the readings of the capacitors around display connectors with a multimeter. We notice this capacitor, the diode readings of its two poles are both 0.
Grab another brand-new logic board and measure it, so its value should be 466V at normal condition.
Do it again, still 0.So this circuit must be cut-off. We are gonna deal with it in a traditional way—rosin.
Apply some rosin with a soldering iron around the corresponding area on the logic board.
Connect this capacitor with power, the rosin is melting.
Put this logic board onto the PCB holder, heat it with a hot air gun and remove this capacitor.(330℃,wind 30)
Measure its value with a multimeter,424V, back to normal.
Get the logic board off, and clean it off with a brush. Connect it to the power and see if it’s still leaking.
0mA, so the logic board is sound.
Disconnect the power, put the logic board onto the PCB holder. Apply some flux paste, replace this old capacitor with a new one. Remove the logic board until it cools down. Install it
Connect the power-on cable, charging cable, display cable and the battery cable. Turn it around, power on. Perfect done.
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