Baseband Common Malfunction - FLY DS 110 Service Manual

3.4.3 Earphone loop
Earphone loop includes headset speaker and
circuit access situation when there is something abnormal (such as: no sound in
headset speaker, Mic invalid, etc.) after inserting the earphone while the headset
accessories are good.

3.5 Baseband common malfunction

3.5.1 Nor flash programming does not download
Data lines used for downloading software: VBAT, TX, RX, GND, CHARGE. It is mostly due
to the false solder and wire bonding. First check whether the serial port of PC and cell
phone is unrestricted, if not, it is caused by being lack of devices or empty solder of power
manager, USB-con and peripheral
using AC-coupled oscilloscope to track the signal flow, if a certain period circuit of no
signal it may be AC short circuit to ground, or is caused by a short circuit and open
circuit. On checking the malfunctions, first should carefully observed the welding of
these devices with a magnifying glass, then plug in the download line to observe whether
the current is normal, there is short-circuit to ground of VCHG or VBAT if the current is
large, at this time
MIC two-way
resistance. Measure the
DS 110 Service menu
signal. Check the
TX, RX signals by
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