Progress bar then whitish screen

[Siggers]

So my 2011 iMac 27inch, won’t boot into anything...

internet recovery - nope
Hdd recovery - nope
Safe mode - won’t work
USB installer - nope
Normal boot: chime white background and black Progress bar with Apple logo, gets to around 3/4 done then white screen dims as if it’s going to pop into login, but just sit there, this is basically what happens on all startup modes, pauses at a white screen.

another working install (different hdd), same deal.

tried swapping ram, reset pram and nvram.

did a hardware test, detected no issues.

Is this a graphics card issue or something more sinister?

 

[TwoH]

GPU issue most likely.

 

[Nguyen Duc Hieu]

Normal boot: chime white background and black Progress bar with Apple logo, gets to around 3/4 done then white screen dims as if it’s going to pop into login, but just sit there, this is basically what happens on all startup modes, pauses at a white screen.

did a hardware test, detected no issues.

1. The only thing you haven't tried is swapping GPU.
2. Showing the progress bar is a light job for the GPU, but display the whole OS desktop, is a more stressful job for it.
=> GPU issue, or logic board issue (not supplying enough power for the GPU).
3. The hardware test does not do the stress test for GPU.

=> Swapping the GPU is an easier solution to detect the problem.

 

[Siggers]

So I swapped the GPU and all good. I hadn’t seen this before.

Can this problem be solved with a reflow short term?

 

[Nguyen Duc Hieu]

So I swapped the GPU and all good. I hadn’t seen this before.

Can this problem be solved with a reflow short term?

The result may vary, depending on the current condition of the MXM card and the reflow method.
Many other just buy another MXM card.
A flashed Quadro K610M is just 36$ + 1~2month waiting.
A non-flashed Quadro K2100M is 90$~105$ + waiting time
What do you think? Are you in the urgency to fix it?

 

[Siggers]

Unfortunately those prices arnt the same in my country (Australia), the 2100 goes for anything from $197 to $540 a card, and they are overseas items. I have reflowed about 5 MXM cards to date, and many other items over the years, only failed on one due to my own fault, I should have paid more attention!

 

[Nguyen Duc Hieu]

Unfortunately those prices arnt the same in my country (Australia), the 2100 goes for anything from $197 to $540 a card, and they are overseas items. I have reflowed about 5 MXM cards to date, and many other items over the years, only failed on one due to my own fault, I should have paid more attention!

The prices above are from Aliexpress, sellers from China.
Living in Vietnam, I had to wait for nearly a month to get it.
Outside of China, the cost of time to get one is the same everywhere, I guess.
Just take note when you order, the shipping cost will vary depending on the size and fragility of the items.