Raptor Computing Systems Hardware > Blackbird

Blackbird Cooling

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MPC7500:
I need to tweak my airflow, too. The default settings aren't good. Because my fan only begin to spin at 30% of the PWM signal.
https://wiki.raptorcs.com/wiki/Fan_Tuning

ejfluhr:
https://www.infineon.com/cms/en/product/power/dc-dc-converters/integrated-power-stages/tda21472/

It looks like that VRM is rated at 60A - 70A in typical ambient temps (e.g. < 40C).   It seems like there must be at least 2 in parallel on VDD, for a capacity of 120+A?   Efficiency falls off as the load gets that high, though.  It would be better to have 3 such stages so they draw only 30A - 40A under normal operation.

cy384:
It looks like there are 7 of the voltage regulator chips, no idea how they're used/wired up though.

Reading about the fan control code and it seems kinda crude, very on/off in design, based more on events rather than target temperatures and dynamic control.  Under max load my CPU fan oscillates between high and medium speeds very noticeably.  I assume this is not an upstream concern, since nobody cares if a server is slightly louder, but it's unpleasant for a workstation.  Raptor spliced in some PID control but I don't think the tuning is ideal.

AFAICT the regulator temperature is considered for fan speed but only after it hits 85C.  Ref https://git.raptorcs.com/git/blackbird-openbmc/tree/meta-rcs/meta-blackbird/recipes-phosphor/fans/phosphor-fan-control-events-config-native/events.yaml

Borley:
Please checkout the cooling idea at DIY 2U heatsink+fan setup. I have my Blackbird stuffed into a slimline mATX case and the low-profile CPU cooler. The temps never really exceed 50C even when gaming.

mx08:
There's an alternative firmware for the BMC on the Blackbird (maybe also Talos 2) called !BMC or bangBMC.

Link: https://gitlab.raptorengineering.com/bangbmc-firmware
Description: https://gitlab.raptorengineering.com/bangbmc-firmware/br-bangbmc/-/blob/raw-first-pass/docs/manual/about.md
Here's the fan daemon: https://gitlab.raptorengineering.com/bangbmc-firmware/op-fan-daemon

It's not mentioned in the wiki AFAICS... It allows to set fan curves at runtime, without requiring recompilation everytime.

I've not used it myself yet and don't know much more than what I've written above.

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