BBAI runs extremely hot

I got 2 BeagleBone AI’s from Mouser and started working with them today.

Both of my boards boot and run with the 08-03 build.

I haven’t done anything to modify the contents of the filesystem, I merely booted and connected via Cloud9.

On both boards, the main CPU heat sink and the Kingston RAM module immediately

heat up and run incredibly hot. I measured >80C on the CPU and >90C on the RAM module with my IR thermometer.

System load looked fine, nothing was running away and stealing all the CPU.

We intend to use these in lieu of BeagleBone Black modules for a project in the Keck telescopes and if they normally run this hot, it will never work.

S/N range is 4000167 1301 003491 1933

Is my experience atypical? What temperature should these boards nominally run at?

Paul

I upgraded the software as recommended by start guide and syslog kept reporting kernel: overtemp, shutdown.

Reflashing appeared to fix that, but mine is still slightly too hot to touch heatsink, heat sink about 50 C

The (Linux) CPU activity LED seems on a lot, when doing nothing (useful).

I'd done a kernel update -- on a booted SD card image -- and on reboot
it did the same... Scrolling temp warning and notice of shutdown (but
apparently spending so much time handling the temp warning it wouldn't
actually shutdown; had to pull the power).

Connecting with ssh I found that out-of-the-box if I ran top or htop the lxqt-panel process was taking a consistent 5% of one of the cores. After updating it increased to 9% (lol). A “killall lxqt-panel” put a stop to that and idle time returned to 99%. The GUI stuff shouldn’t even be running without a valid HDMI HDID, right? Can’t wait to get a console image working and leave all that GUI junk behind…

I had the same thermal problem and my board shut down by itself. I was able to solve this problem by placing an 80mm fan on top of the board. This fan has the usual 3 wires and I connected the red wire to 5V Sys (P9-7) and the black to GND in P9-1. The entire board now runs cool to the touch.

Looks similar to me. Updated to latest images and get:

`
kernel:[ 709.540231] thermal thermal_zone0: critical temperature reached (80 C), shutting down

`

@Paul - Would you be able to take a close up picture of the backside solder points of the serial debug connector (3 pin next to USB C)?

My AI was overheating too until it stopped booting all together. I was looking to monitor serial as I applied power and that is when I noticed what appeared to be an unclean solder point…its not shorted there is a 99kOhm resistance between the two points.

https://drive.google.com/file/d/19pRcHcP9APTcQ6nWiU708ca8ID9PtNXH/view?usp=sharing

Mike

@Paul - Would you be able to take a close up picture of the backside
solder points of the serial debug connector (3 pin next to USB C)?

  Not "Paul" but... attached image I hope

My AI was overheating too until it stopped booting all together. I was
looking to monitor serial as I applied power and that is when I noticed
what appeared to be an unclean solder point...its not shorted there is a
99kOhm resistance between the two points.

  Similar... Do I take a needle file to it, or risk a soldering gun... Or
complain to Newark about a defect...

solder_bridge.jpg

Isn’t that just a pull-up or pull-down resistor? My board has it too.

https://github.com/beagleboard/beaglebone-ai/wiki/System-Reference-Manual#223-rev-a1a

Ted Roth

Theodore is correct, pull-down on debug serial RX, it is in the release notes https://github.com/beagleboard/beaglebone-ai/issues/24

I assumed the PCB layout had been changed.

Yes, a hand-soldered pulldown:

BBAI_serial_pulldown.JPG

That may have been the attempt, but looking at mine (see previous
attachment) the resistor has been completely covered with solder, and
solder also fills in the area under it down to the board level.

@Paul - Would you be able to take a close up picture of the backside solder points of the serial debug connector (3 pin next to USB C)?

My AI was overheating too until it stopped booting all together. I was looking to monitor serial as I applied power and that is when I noticed what appeared to be an unclean solder point…its not shorted there is a 99kOhm resistance between the two points.

https://drive.google.com/file/d/19pRcHcP9APTcQ6nWiU708ca8ID9PtNXH/view?usp=sharing

Exactly, it is intentional.

https://github.com/beagleboard/beaglebone-ai/wiki/System-Reference-Manual#rev-a1a

If you are running the device headless (no display attached) you can disable a few things that are display related in the device tree (HDMI, GPU). That will eliminate about 500mW of power consumption / heat. You should also disable lightdm (lxqtpanel process is constantly using 10% of the CPU).

Finally, if you’re fanless get a different heat sink! The included one is only meant for fans. This is the one I’m using: https://ebay.us/RUFBGy

With a better heat sink and disabling GPU my idle temperatures are 55C rather than 80C even with the cpu governor set to “ondemand”.

omapconf printout (with MPU at 1GHz minimum)
https://drive.google.com/drive/folders/1KZsn9ltf-R-VHqQGgLYPkqb5b8XhGxpV?usp=sharing

Hi Paul.

I see the same. I’m using the base OS as shipped (Debian 2019-08-03). I upgraded Debian and I upgraded my kernel with the tool in /opt to get to version 4.14.108-ti-r119.

If I just let the machine idle at the desktop it will get hot and shut down after a few minutes.

We want to use this as a controller without active cooling.

Is this software and drivers? Is this hardware? Is there a reasonable expectation that we could run the board with high load without a fan?

Is there a way to throttle processor?

Thanks,
Harry