I’ve come across another rabbit hole switch, The switch wont boot or display anything.
It is a v1 hac-cpu-20
I can successfully send a payload which turns the backlight on but does not display anything
Originally the board on its own would draw 0.07a constantly and successfully negotiates 15v
After I removed the nand and connected it back to the board it now draws 0.00a and occasionally jumps from 0.00a to 0.05a to 0.08a to 0.00a.
If i remove the nand the board draws a constant 0.07a to 0.08a
When powered with an original charger I get all the expected rails except the 0v8 cpu.
The max ic below the apu that should output the above rail does not seem to be enabled
It has the expected 4.2v and 1.8v readings on the nearby caps
Lastly everything on the board is clean and shows no sighs of being worked on,
I suspect this may have been a victim of a drop although the shell looks pristine
Rail → black on ground
0v8 CPU → 375 Ω
0v8 GPU → 51 Ω
1v1 → 1.18k Ω
1v8 → 5.08k Ω
1v15 → 40 Ω
1v35 → 600k / 3.6m Ω
3v3 → 178k Ω
5v → 3.3k Ω
Sys → ~670k Ω
If anyone has an idea or something obvious that I missed, please let me know!