Goal: Make sure efuses are soldered properly & Test efuses over current protection and short circuit protections
Pre-test preparation:
Try to borrow an eload from Rover or Midnight Sun,
if you can’t borrow the eload, make your own eload. Find the XT60 connector with around 10 resistors soldered together, it should have resistance labelled on it, around 1.67 ohm if I recall correctly. It is in a yellow connector organizer kit.
Set up eload if you can borrow one
Set up scope
Vin channel
Vout channel
Iout channel, for this you need a current probe and it needs a 9V alkaline battery (Rockery has 9V battery if we don’t have any battery left)
Lift R1 to disable buck
Solder a wire at C15, connect power supply here to inject 6V
For each efuse,
Solder 2 wires at output, use one wire for load and another wire to measure Vout;
Solder 1 wire at input to measure Vin
Solder 2 ground wires
Test plan:
Check
No shorts caused by soldering rework on the PCB
Vout is 6V
Current Probe is working
Over Current Test
Set eload to CC mode, load 1.2A, keep the load off
Set Oscilloscope to Normal, trigger around 0.1 - 0.3A, we want to see the efuse retrying
Turn on power supply
Turn on eload
Take a photo of Oscilloscope screen
Repeat for all efuses
Short-to-ground Test
Set Oscilloscope to Normal, trigger around 0.1 - 0.3A, we want to see the efuse retrying
Turn on power supply
use the load wire at efuse output, short it to any ground on the PCB (seeing spark is fine)
Take a photo of Oscilloscope screen
Repeat for all efuses
Battery Inrush Test
make sure to use a old battery
Solder input XT60 connector
Probe Buck Vin, Sw node, Buck Vout, Buck Iout. Label the channels
Set eload to Load imax which is 4A at buck output
Set eload slew rate to max
Turn on eload
Set oscilloscope to single, trigger on half of buck vin rising edge
Plug in battery
Pray nothing burns lol
Take a photo of oscilloscope screen