Kasli 2.0 fan control

lriesebos

I know there has been a lot of discussion around bad radian fans on Kasli 2.0, but my question is a bit different. I noticed the fan speed is PWM controlled, but I cannot find any references to a PWM controlled fan in the firmware. Is the fan always supposed to run at full duty cycle, or is it somehow temperature controlled by the FPGA or the firmware? And is that behavior be the same for master and satellite firmware?

Wondering because I noticed the fan on a satellite crate is not rotating while the fan is not a radian (it is the other recommended model), tested to work fine, and the pins for the fan do read 12v with a multi-meter.

sb10q

The PWM should not be used with the current hardware and the fan should run at 100%. Same issue as found on Thermostat https://github.com/sinara-hw/Thermostat/issues/115

sb10q

Is the polarity of the fan correct?

lriesebos

Yes, we checked the polarity of the old radian fan as well as the new fans. We are not trying to control them with PWM, just noticed it in the schematics. Regardless, it seems that is not being used. I will try to verify tomorrow with a scope that the 12v we measure is not pulsed. So assuming that is all fine, could there be a situation where not enough current is provided to make the fan rotate?

lriesebos

From M-Labs support:

Does the wire polarity of old fans connector matches new ones? The newer ones have "protection" mechanism against wrong polarity, which may melt the mosfet under the fan connector. As per our recent experience, we suspect that may be the issue.

This might have happened during maintenance. We'll fix that, but good to know this. Tnx!