MBPro late 2011 keeps on rebooting

[Giuanniello]

Long story short (I always try but never manage)
this is one of the MBPro with faulty graphic board, the mainboard was changed after a class action and it has kept working fine till a certain point.

Removed the spinning drive for an SSD and it got much quicker but fans always on so I cleaned them off dust, run a Diagnostic test and one of the RAM modules was faulty, replaced them and it run for a while but then would only boot in Safe mode which makes it super slow and almost a paper holder.

Tried again today to swap to a spinning disk since last time it used to work fine with it but same issue, it can't get to boot, run a full Diagnostic test but no fault off of it.

What would you try to make it work?

Grazie

 

[Analias]

What does it do exactly? Do you get the apple logo and then just a white screen?

 

[Giuanniello]

It shows the loading bar and then reboots, yesterday it finally completed the boot sequence and is now working but I don't know what to look for as the cause of this issue

 

[Analias]

13" or 15"?

 

[Queen6]

Try putting the original RAM back in one stick at a time. MBP,s can be very particular about RAM.

Q-6

 

[Analias]

After rereading OP I gather it is a 15". Just over halfway through the loading bar is where the low level system hands off graphics tasks to the os and gpu. A fault here in a 13" is indicative of a ram problem as the os assigns some ram to the integrated gpu. As yours is a 15" it is indicative of a failed discrete gpu. When Apple replaced your board, they didn't replace it with one without the fault, and it was destined to fail in exactly the same way. Your only reliable option is to flash the gmux chip with dosdude1's modified version "demux". https://doslabelectronics.com/Demux.html