IamDefiler
there is a thermal pad on the Soc and the TDA7808 sound chip, and the whole back plate is the heat sink
Dudu7 head unit reboots by itself
Yes sim card inserted and data is always on
Hi. I'm having the same problem. I bought my unit about 8 months ago. After 15 days of use, it started having reboot issues until it stopped working. I removed it from the vehicle and didn't use it for several months. A month ago, I plugged it outside the car into a power source and it turned on. But it kept rebooting. I accidentally installed AIDA64 and noticed the high temperatures. I replaced the thermal pad with a 0.8 mm thick aluminum plate and thermal paste. I managed to get the unit to work stably with idle temperatures below 40 degrees and maximum temperatures of 50 degrees. But after 7 days, it started rebooting again. I don't know what to do. They are defective Unisoc 7870 units. I already complained to the seller, but they are no longer under warranty.
Since I was already giving up on the issue, I decided to test the unit without any interface on the processor. The unit booted normally, reaching 100°C without rebooting or shutting down. So I decided to test again with a replacement thermal pad that usually comes with M2 drive heatsinks. And surprise, I once again got stable temperatures of 50°C without rebooting, and maximum temperatures of 72°C with a CPU stress test. Very strange, because I had already tried using these thermal pads without good results.
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Arielnac Could you provide photos with the backplate off? Could the backplate be trapping heat against the circuit board and maybe affecting other chips possibly causing the reboots? Maybe the SOC overheating isn't the issue.
IamDefiler Hi. No Friend. When the unit fails, the CPU temperature readings are high. When it's working properly, the temperature readings are much lower. The problem is the CPU.
Arielnac Only reason I asked was because of what you stated above. "The unit booted normally, reaching 100°C without rebooting or shutting down."
Mongcharlie I also have SIM card inserted and data always on. My unit is continuing to reboot randomly (approx once a day when in use for several hours). It is frustrating when using it for navigation on unfamiliar busy city roads. I am now thinking the only solution may be warranty claim with seller.
7 days later
IamDefiler Yes. But that was just a test condition, without subjecting the processor to any type of load, and to see if there really is any difference between placing some type of interface between the CPU chip and the aluminum heatsink. And there is. The problem is that under load, at some point, the CPU temperature shoots up and it either reboots or crashes. I've verified this because while AIDA 64 shows me temperature values below 50 degrees, the unit runs stable. When it starts showing values above 70 degrees, just listening to music with a low CPU load that doesn't justify that operating temperature, it's just a matter of time before a reboot or crash occurs.
The factory fan may have too low airflow. You'd need to remove the factory fan and replace it with a 40 x 40 x 25 mm fan to increase the airflow over the aluminum heatsink.
Arielnac I understand. Thank you.
IamDefiler What may be happening is that when the outer casing heats up a bit due to the audio amplifier chip, the air blown by the fan over the internal CPU heatsink is too hot and doesn't generate enough temperature gradient to cool the CPU. Removing the factory fan and installing a 40 x 40 x 20 cm external fan in the same air intake location would likely generate enough temperature gradient.
Arielnac what is the voltage of the stock fan? I have been thinking about updating mine, but would like to order a fan before tearing it apart.