Thank you very much Handycracker2k2, this info is a great help !

My DM5620 is dead.... i noticed a leak on the 2200 uF condenser on the main board (near power supply connector), i measured it and noticed it was in short circuit and so I changed it, but maybe the short circuit destroyed something into the power supply... I changed a lot of parts on the power supply (condensers, mosfet, photo-insulator, ICs...) but no luck !
Maybe the problem is in one of the SMD components (the B3842 or the FET), but without a schematic diagram is very difficult to track the problem.
Can somebody help me ? In particular some infos that can be very useful are:

1) What voltages should the power supply provide to the mainboard and on what pins of the connector (btw having this info i could simply replace the entire power supply...)

2) Is it possible to buy from DMM a replacement power supply ? How ?

3) Is a shematic diagram of the power supply available ?

Thanks to everybody !