Geeetech

This is how i measured the voltage, i didnt take a photo because this is easier to explain how i did it, also remember ....the voltage from the fan output on the board is the same (3.3v) so i am thinking there is definitely something wrong with the PSU.....what do you think

Test the DC voltage between A and C, the DC voltage between B and D. They should always be 12 V.

Well that's what I did, the DC voltage is always 3.3 v

It has been 3 days since you have replied,you think it is the PSU ?can i use any psu ? or just the geeetech brand ?

Sorry for replying so late because of power outage.
Yes, the issue exists in power supply.
You can buy another brands of PSU, but there must be 2 groups of 12V output voltage, and the current should be more than 20A.

thank you for replying, i just want to be sure about something,the PSU the company sent me was 12v 15A, and now you tell me it is supposed to be 12v 20 A...the supplier is going to send me a new one , and i would appreciate it if you are sure which one to send me ,although the manual specifically says it is 12v 15A. please reply

Oh, my advice is based on: In case you want to upgrade your printer to dual extruder, you don't need to replace a new PSU with higher current.
Yes, 15A is enough for single extruder. Sorry for my incomplete description.

Dear friend, thank you for your help, hope the printer works fine, i an posting the results as soon as i receive the Psu