Hi everyone,
just have bought a Jetson Nano (B01) kit and experiencing the following issue:
I have a case with power button and the appropriate jumper is placed on the board. The fan (Waveshare 4010-pwm-5v) is attached to the 4-wired connector. When I power on the case but the board is off, the fan starts working at the maximum speed and when I press the power button (so to power on the board) the fan lessens its speed to the minimal (the board takes over the control and the temperature is minimal, I guess. That’s ok).
I checked all the stuff with an oscilloscope and found out that:
- the fan being powered on separately (without pwm signal) provides pullup to 3v on the pwm wire and works at the maximum speed.
- if the pwm wire is pulled down, the fan works at the minimum speed (6Hz).
- the board when unpowered seems to keep this wire in a Z-state and that’s why the fan is going mad.
I assume that certain state of the pwm line should stop the fan completely, but I don’t know if the problem is with the fan or the board in my case…
Please if anyone could check on his/her correctly working Nano, what are the correct levels of the pwm wire when:
- the case is powered on, the board is not?
- the case is powered on, the board too?
- the fan is powered on separately (detached from the board)?