Whoa! I tried powering the fan from 3.3 V, but it seemed to be rotating so slowly that it wouldn't do anything. At 5 V it appeared to move a little bit of air, and was almost silent.You can't see it on the photo, but that connector supplies 12 V, which is why the fan sounded like a jet engine.
I still have the fan; I may try to run that off of 5 V or 3.3 V, as you'd suggested, and see if the noise is tolerable. I doesn't take much airflow the get the temperature down to where the video stops glitching. Just a gentle sustained breath of air works.
So I put it all back together, and after 10 minutes of warming up, the CPU has stabilized at <50 ºC! And the video is working properly.
I tried backing off to 3.3 V, and it still keeps the temp <60 ºC, and now it's effectively silent. I should still have pretty decent thermal margin for hot days in the warehouse.
I didn't realize that such a small amount of airflow could make such a large temperature difference, and the fan isn't even directly above the chips. Thanks!
Statistics: Posted by TheWaterbug — Wed Sep 18, 2024 12:01 am