jpmathew
Posts: 9
Joined: Wed Oct 10, 2012 2:21 pm

HDMI failure on Pi 3 B after overheating

Mon Apr 03, 2017 5:33 am

I got my 3rd Raspberry Pi 3 B from Element14 in India and soon after I booted with Raspbian and within a few minutes, the HDMI display showed noise lines and finally the display totally failed. The Raspbian was working, as I could ssh into it. Subsequent reboots caused the HDMI to be blank, but system working with ssh. The "vcgencmd measure_temp" showed 44 and rising up to 50 very fast.
If I chill the Pi and then power on, I am able to get the display for about 5 minutes, and then when it heats up, and the display fails. With config_hdmi_boost=11 it works for a bit longer, but after sometime that too fails.
Issue seems to be that of SoC overheating. But I am puzzled not understanding which part of SoC reduces the signal strength that is going to HDMI with a "normal" heating level of SoC. I am in Kolkata and in March the normal room temperature is a bit hot!
Is there anything I can check before I try for a return of the board?
Thanks a lot to Raspberry Pi team.

ktb
Posts: 1384
Joined: Fri Dec 26, 2014 7:53 pm

Re: HDMI failure on Pi 3 B after overheating

Mon Apr 03, 2017 8:13 am

Is the temperature really only reaching 50 °C or does it go much higher? 50 °C isn't very hot in my opinion. The measure_temp readings on my Pi3B have gotten much hotter than that in certain scenarios without causing any problems for me.

jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 24577
Joined: Sat Jul 30, 2011 7:41 pm

Re: HDMI failure on Pi 3 B after overheating

Mon Apr 03, 2017 9:14 am

That sounds like a defective board - 50 isn't all that hot - it can go to 85'C before it starts to throttle the CPU.
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jpmathew
Posts: 9
Joined: Wed Oct 10, 2012 2:21 pm

Re: HDMI failure on Pi 3 B after overheating

Mon Apr 03, 2017 9:59 am

jamesh wrote:That sounds like a defective board - 50 isn't all that hot - it can go to 85'C before it starts to throttle the CPU.
Thanks jamesh. The point is that this board worked for an hour before it failed. Here I tend to believe that overheating caused the "damage" to the SoC. If so, should we all use a heat sink on the Pi 3 B models to avoid future failures. I never had a case of Pi 2 failure, and I can feel the Pi 3 gets rather hot.
If Liz views this : Is there a history of similar failures with RPF
Since config_hdmi_boost=11 made it work a wee bit better, I had this question, how does the GPU change signal strength?

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