Read JBL SPARK Service Manual online
4-2 Trouble shooting Chart
No Sound
No Sound
Go
Yes
Measure the pin20/21/22(IIS) of U16
to
check the IIS signals whether exist or not
NO
BT module is broken
No
Yes
Check the voltage of PIN19 of U16,
H level is normal
Check the voltage of FB19, 13V is normal.
Check in step with “ Can not power on”
No
No
N
N
NO
Yes
Check signals of L2/L3/L4/L5
PWM is normal
No
U16 is broken
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