August 4th, 2016, 17:43
August 4th, 2016, 22:32
August 5th, 2016, 9:25
August 5th, 2016, 16:16
August 6th, 2016, 13:13
August 6th, 2016, 14:03
August 6th, 2016, 15:46
August 6th, 2016, 17:44
August 6th, 2016, 18:12
August 6th, 2016, 18:17
August 6th, 2016, 18:24
August 6th, 2016, 18:41
August 6th, 2016, 21:47
August 7th, 2016, 8:03
Check the EN(able) and ENCH inputs of the various chips. EN should be high if the chip is enabled, or low (0V) if the chip is disabled. I expect (and hope) that EN will be low, as this would point to a common factor.
There is a fourth regulator (V4) which is shrouded in darkness in one corner of the board.
The OAH LDO regulator has an input voltage (Vin) of only 2.75V. IIUC, this voltage is too low (Vout should be 3.3V), in which case the source of Vin must be suspect.
Can you measure the resistance between the Drain and Source pins of the MOSFET switch? As mentioned before, the Gate voltage is not consistent with an ON state.
Can you identify the markings on ICx and Dy (does Dy have a polarity stripe?) ?
Can you measure the voltages on the capacitors adjacent to ICy? Is the IC marking CY or QY? I think I may have incorrectly identified it.
August 7th, 2016, 8:40
There's some heat generation in this IC (see flir attachment). I'm guessing this is the primary suspect.
August 7th, 2016, 8:59
August 7th, 2016, 10:54
August 7th, 2016, 15:20
August 7th, 2016, 15:32
August 7th, 2016, 15:54
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