Blackvue 650 Immediate Power Down (no hold up)

Steve750

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OK, this post is a little technical, but here goes.
Blackvue 650GW-2CH was giving problems (random resetting, "Please Check SD Card" issues, etc). Also noticed that the unit would immediately shut down when power was removed (it no longer waited a few seconds and would no longer say "shutting down")...
So, after some research, I found the RTC battery might be one of the issues, so I replaced that. Next, to address the immediate power down issue... I figured the super cap was dead and that would be an easy fix. However, when I opened up the unit, the cap was fully charged to 5Vdc. I also noticed that when I powered down the unit, the 3.3_LDO and 1.8_LDO voltages would go immediately to 0Vdc even though the cap would stay fully charge to 5Vdc. Thus, it's pretty clear that the Low Drop Out circuit that makes 1.8Vdc and 3.3Vdc from the super cap voltage is no longer working. Does anyone have any insight into the circuit design of the power board? I'm sure there is an LDO (low drop out) regulator somewhere that uses the 5Vdc super cap voltage to generate the 3.3_LDO and 1.8_LDO voltages, however, I haven't yet been able to successfully trace the circuits; and I haven't been able to identify which device is the LDO regulator (the SMD chip markings get cryptic on such small devices). A schematic and layout would be ever so helpful to identify and repair the LDO circuit.

Finally, just an interesting tid bit; the 650 uses the same exact power board as the 550 (the power board is actually marked 550). So this problem/question/issue applies to the 650 and the 550 (and probably others).
 

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