The iPhone 6 Plus touch screen does not
respond after dropping into water and the display and touch screen socket has
been replaced. But it’s still not working. What can we do in this case? pls
follow the Vipprog to solve it.
The touch screen circuit of iPhone 6S is
quite different from that of iPhone 6. The touch control or process chips are
all assembled to the display assembly. The display screen and touch screen share the same socket. The
material object of iPhone 6S display and touch screen socket is shown in
picture 1-1.
1-1
When the display and touch chips are
assembled at the screen assembly, motherboard only supplies power to touch screen circuit,
clock, reset, INT signal and SPI bus. During the repair process, when iPhone
has no touch problems and the displays normally after being turned on, we do not
have to measure PN5V7_LCM_MESON_AVDDH, PP5V7_MESON_AVDDH and PP5V7_LCM_AVDDH.
Because they are shared by display screen and touch screen. The voltage circuit diagram of display and touch screen is
shown in picture 1-2.
1-2
In general, we just need use multimeter to measure the diode data of part of pins
of display and touch screen socket J4200. And measure the voltage of
PP5V1_TOUCH_VDDH and PP1V8 after assembling display screen and turning on
iPhone. The measuring points are shown as these yellow points in picture 1-3.The
diode data and voltage are normal after being measured. Replace the display
assembly and measure again, the touch screen still cannot respond.
1-3
As iPhone 6S has the 3D touch
function, the abnormal 3D touch function can cause unresponsive touch screen.
3D touch function is connected to fingerprintsocket. Thus we measure the diode data of fingerprint socket and
we find the diode data of reset signal AP_TO_TOUCH_RESET_L is being a little
small- just over 80. While the normal one should be about 400. After checking
the bitmap, we know the reset signal AP_TO_TOUCH_RESET_L is interlinked with
display and touch screen socket, as shown as the yellow points in picture 1-4.
But, the diode data of AP_TO_TOUCH_RESET_CONN_L on J4200 is normal.
1-4
Finally, the measurement shows that the
AP_TO_TOUCH_RESET_CONN_L on display and touch screen socket on display and
touch screen socket is not linked with the AP_TO_TOUCH_RESET_CONN_L on
fingerprint socket. Tear up the black adhesive tape on the edge of fingerprint
socket and we can see that the several components on the edge of FL4134 and
C4134 are corroded. After cleaning the corroded components, turn on iPhone and
get into IOS test. The touch screen and 3D function can respond normally. The
corroded components are shown in bitmap picture 1-5.
1-5
No comments:
Post a Comment