The iPhone 6 accidentally dropped into water, and then a series of issues came up. It has no response when press iPhone power button, and it shows big current, which means it is short circuit. The direct big current current is 5A and the voltage is pulled down, the systom is usually caused by serious short-circuit of the iPhone battery direct power supply components or PP_VCC_MAIN power supply components. Now, we need to fix it!
The
main chip (yellow) connected to the positive electrode of the battery is shown
in picture 9-2-1 .
1:
Pick the hottest chip to remove, After the Q1403 is removed, the power
supply is still large and short-circuit, which proves that the problem lies in
the direct power supply element of the battery. Just clip a PP_VCC_MAIN to 4V
and press the power button to enter the system, but there is no touch function.
2:
The capacitances around U1601、U1400、U_2GPA_RF are all measured as short circuit,
continue to clip with 4V find the parts below the iPhoneNAND Flash are all hot, it's still hot after removing U1601 and
U1400, finally, we remove the iPhone charging chip,
high frequency antenna switch, 2G function, a charging tube, audio amplifier,
vibrator, but it is still hot.
It's
strange that we find baseband power and baseband CPU is also hot, they are not
related with direct power supply. After careful observation on baseband power,
seems that the baseband power was artificially moved before, so we remove it
first. So we replace the new baseband power supply, there is no short circuit
now, so reballing the chips that removed before —— reboot phone and enter the
desktop, but it 's still unable to touch.
3:
Measuring the end of capacitance C2402 connected to the U2401, there is no
5.1V voltage, apply VC890C+ multimeter measuring resistance is
570, sub touch screen positive 5.7V is normal, resistance 438, sub touch screen
-5.7V is normal, resistance 580, power supply +13.5V is only +5.73V, -12V power
supply is only -5.56V.
4:
The
U2401 was reballed but still completely cannot touched, now we replace the new
U2401, its touch function returns to be normal, but there was a vertical wire
on the left that could not be touched, the icon could not move, and it could
only move up and down. As shown in picture 9-2-2.
No
touch fault is generally caused by the communication problems between U2401 and
U2402 wires , now we find C2427 is missing.
Install
the C2427 parts at same position, touch completely finally can work normally,
after function tested, we find the iPhone 6 HOME
button and WIFI can not be
used, after the working voltage measurement on WIFI, WIFI_VIN_1P35 voltage
result is found not normal with +3.93V, the fault is still existing after the
replacement of L5201_RF.
5:
Remove
the U5201_RF while measuring the chip 36 pin (clock) resistance is not
infinite, the voltage 0.8V is normal,
Measuring
WIFI start signal resistance is not infinite, the voltage +1.8V is normal, as
shown in figure 9-2-3 .
6:
Finally,
after the iPhone WIFI chip was reballed
again and the fingerprint flex cable element was welded.
Finally, assemble iPhone 6, power on it and test it, all the function is normal , the iPhone 6 has been repaired!
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