Hello,
some news, so as the spare parts are more than half the price of a new drill, I bought the same drill again.
After a few tests, there is again some play on the mandrel. On a 10mm drill bit, I have about 1,5 mm play at the tip of the bit (yes, I checked that the bit was straight, I have no play at all on my floor drill press), which induce inaccuracy and a lot of vibration.
So I returned the new drill. I think I will change for a Makita or Bosch (which are unfortunately more expensive)