Just registered to tell how I've fixed the steady red light problem on mini 0805 dash cam (cam not turning on). I believe 0806 and other cams sharing the same hardware may have the same issue.
So failure history:
0805 bought from GB, after several months of service suddenly not turning on, only steady red led on when power is plugged. Not identified by DirectUSB, no reaction on SD-card with firmware, nor any other signs of life. The cam was put in the drawer and forgotten for more than a year but today I found it and decided to investigate.
Solution:
Ambarella just like any other ARM is supposed to have some regulated standby power supply. I measured around it and there was nothing. Obviously, something was wrong with the power supply. Looking around I've found a test point after an LDO (linear regulator) which was 0 while it should be something. LDO is pointed with a red arrow, test point with a blue one on the image below. The stain near LDO is some flux as I took pictures after desoldering the part. That's not a burn mark.
View attachment 33152
The LDO was dead. I don't know what was the initial voltage rating of this LDO but suppose it was from 3 to 3.3V. Pinout is similar to MCP1700T-33002E/TT from microcheap (yeah, chip). I didn't have one like that but found TI's LP2950-33 in TO-92 through-hole package, it has 3.3V output voltage and enough current margin... So having the pins trimmed, I soldered TI part in TO-92 instead of the original one minding the pinout difference. There's enough space inside the plastic case of 0805/0806 for this kind of workaround. The LDO is in the red square. After connecting the battery I surely measured 3.3V on the test-point.
View attachment 33154
After plugging the power supply the camera turned one. If you're going to use a non-standard component, make sure to put some tape around the battery not to short-circuit the LDO pins.
As for the root cause of this failure - I suppose that's standard chinese economy when every cent is counted to make the product cheaper so some cheap underrated components were installed instead of what was originally specified by the design.
Hope that post will be helpful.