A1398 Restarts After Password Logged In

[MeTech Turkey]

I have my customer’s computer which restarts after we put the password and press enter. It restarts again and again after I put the password but after several restart it logges in.
Where should I start looking at?
Thank you

 

[2informaticos]

What is the MLB code?
Does it have discrete graphics?
Did you try starting in safe mode?

 

[MeTech Turkey]

The MLB code is 820-3332-A
There is a discrete graphics
What I found out is the diagnostic mode is not starting with “D” key. It gives an cannot load testsupport.efi error
The headphone jack has a problem it does not recognise the headphones. It recognise always as a optical speaker.
and the battery been replaced. I am not sure but I think when the battery been connected it starts the fans full speed. This problem can be caused because of battery?
We did a clean mac os restore but still doing the same by the way.
When it restarts after we put the password and hit enter it restarts itself for 2- 5 times then let us to log in.

 

[2informaticos]

Test with original battery.
I saw very weird issues caused by chinese batteries on these machines.

Just in case, try known good BIOS, clean ME.

820-3332 DKQ1 clean ME.bin

drive.google.com

 

[MeTech Turkey]

One more question we had the same problem without battery plugged in so can we still say it is still can be the battery?

 

[2informaticos]

You should be able to load macOS without battery.