Screws may loosen due to shipping. Although I have only experienced this with the FETs' fasteners.
As a precaution, I also wrote and added longer fixing screws so that the screw is not only held by the threaded insert pressed into the heatsink.
A thread or a hole must also be made in the cooling fin, and a longer screw provides better protection against loosening.
Those who occasionally read the forum did not notice this information.
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Gyula HA3HZ
HA3HZ