Horizontal Lines after PRAM

Thanks for your reply.

No joy unfortunatley. Straight to the Absolute Horror.

I've tried every possible start up key combination and also after the PRAM 2nd beep when the screen becomes good.

@deadbob - Not good 😩 😖

This test tells us the T-CON board which is part of the display assembly has failed.

The test you did switched access to the Intel graphics engine over the normal discrete AMD GPU chip. If the AMD GPU was the issue then your system would have worked!

You’ll need a new display assembly review this guide which offers the parts info MacBook Pro 15" Unibody Late 2011 Display Replacement

If the AMD GPU has failed (universal problem with this generation of MBPs) you need to disable it so it runs on the internal one only

I am not convinced that the test run by the OP shows that the internal GPU has an issue - what he describes is exactly the problem I had with my 2011 MBP 17

The instructions are here: https://dosdude1.com/gpudisable/

You may not be able to see the screen clearly because of the stripy screen when you run the first step (Cmd+S) but carefully make sure you type the code in as per the instructions - it definitely works and once it is disabled, you should be ok

Please note that if you reset the NVRAM again after this, the problem will reoccur and you will need to follow the instructions again!

@simon64439 - You can also use the D or T keys to achieve the same. The issue first does the system even try to startup. If that is the case the Startup keys will effectively hold the system to the Intel CPUs graphics engine not using the AMD GPU. if the system is not achieving that then one often needs to disconnect the battery as well as MagSafe and then hold the power button to fully discharge the logic board as SMC maybe in the latched state which is when it encounters a major failure.

The DOS DUDE solution also works! But again you need to be past the firmware IPL (SMC) state.

Thank you for your replies. I have been very busy but finally got around to trying it out.

It works, screen is functioning, all is clear but now I can only boot in safe mode or pre OS modes.

If not in safe mode it attempts to boot and then restarts to do the same thing.

Any ideas?

Many thanks

Yes. @Nick beat me to it but this is the answer. The key is here:

"Also we the same problem occurs when using an external monitor."

External monitor exhibiting the same symptoms is GPU issue. On your MacBook Pro, the GPU is integrated into the main logic board and cannot be replaced, and this issue cannot be repaired. Sorry.

While it is possible to replace the logic board, the cost and time required of such is usually the same if not more than the value of buying a replacement computer entirely.

@erelectronics Get the Mid-2012 15". They do not have the same problem. While you can swap the MLB, it's usually as much as a whole unit unless it has special options we want like the 1680x1050 AG screen. When I was looking for a 2011 17" to replace my 2009 17" I lost years ago due to a bad MLB, that screen was a non-negotiable option even though it costs you; a 1200p panel IS guaranteed.

This GPU issue ended the search for me >_<. Thankfully we got the 16" M series (which is basically the 17" all over again but with modern hardware) to take on the legacy of the 17".

@nick @erelectronics - The test I had Jonathan do, proves the issue is not the discrete AMD GPU.

If that was the case the test forcing the use of the Intel CPUs built-in graphics engine would have worked! As that is not what happened the issue is the display!

Yes the 2011 AMD GPU has its issues! But it’s often accused as the problem when it’s not. The problem with this series AMD GPU is running heavy graphics! If you are not pushing it it’s not a problem.

@danj Yes. I did not specify the AMD GPU or the Intel GPU because that info was not enough to determine if it was one or the other, but either one is still how the logic board processes the images. I apologize if that was not clear, I was trying to use vague language because it could be either of them, or the part of the logic board that processes video after the GPU itself. But it is all part of the GPU "package", as it were, and if it fails it cannot be reliably fixed.

@erelectronics - if it was the AMD GPU I can still get this system working! Which is why I wanted the test as we can force the logic to use the Intel graphics engine.

Think of it this way… A 13” doesn’t have the AMD GPU it uses the Intel graphics engine. So if we force this system to that state this would be a workable solution. Correct?