FLY DS 110, Service Manual

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DS 110 Service menu
cut off power supply as soon as possible, and then find the short-circuit point. It may be
the abnormal output power supply of a certain circuit that the current is larger than normal
(about 30 mA) but not particularly large, at this time should check whethe the valgate of
VCORE (1.8V), VDD (2.8V), VADD (2.8 V), VTCXO (2.8V), VRTC (1.5V), VMEM (2.8V) is
noamal, if not, bad welding can be detected. Focus on checking the welding of PMU and
USB-CON if there is a little or no current. Unplug and re-plug the download line to see if it
is caused by poor contact; It can test that whether the output of 26MHz clock signal to the
CPU is normal by using oscilloscope.
3.5.2 Detection and Maintenance Flow Chart of No download
malfunction
Not download
Eliminate any
reasons for not
download except
the cell phone.
Yes
Check whether it is the problems
of allocation of procedure,
download cable, power supply,
software, PC phone.
Check whether
the 5pin
connector USB-CON
is false soldered
or
damaged.
NO
NO Check whether the serial port of
PC and cell phone is unrestricted.
NO
Check USB-
con peripheral
resistance
Yes
Connect the download line
and observe the ammeter whether
the current is high (normal current
is generally about 30mA).
Yes
Quickly disconnect
the connection, and
touch the chip gently to
see if it is hot, if not,
focus on measuring
the short-circuit
point by using
multimeter.
A little or no current
Normal current but no download
Check whether the voltage supply of CPU
power manager, PMU and LDO is normal,
whether there is any power supply open circuit.
Check VCOR
、
VDD
、
VADD
VTCXO
、
VRTC
、
VMEM
、
measure the
clock signals of 26MHZ
、
32KHZ
Check whether CUP and NORFLASH
is OK, LDO is normal?
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