Hi community

I just bought at a chinese retailer a DPS-1200FB PSU.

It sounds to run normally except that :

1° When powering on, it does not do the usual cycle with fan running @ max few minutes. Instead, it stays quiet, running at very low RPM, almost impossible to hear.
2° When loaded ~600/700W, the fan remains at the same stock speed than without any load. However the metal case become very hot. ( Impossible to let finger more than a second on )
To prevent any frying I set on top 2 heatsink cooled with 120mm as a temporary solution.
3° Last but not least, output airflow smells hot compound, something like fried than shouldn't be that much to my mind.
I don't tell it's burning, but it has sucpicious smell.
4° The more I let the PSU without cooling, the more my rig tends to crash

Do you think this PSU has been tweaked and sold with low noise adjustment for popular need ( noise killing )?
Is it about to die because of worn out ?

Any advice appreciated and moreover the mod consisting of raising fan level

Friendly