Recently, upgrade iMac memory from 4GB each to 8GB. Officially this 2011 iMac only supports 4GB each, but 8GB memory can be installed.
It can also install mixed memory size and mixed speed. I also installed the memory which supported both 1.3v and 1.5v.
Got buzzing noise from top left corner, and very hard to turn on, power button may or may not response.
The fan noise also comes from bottom right corner, thinking to replace a new one.
The power button got issue long ago, sometimes can not work, sometimes can. I think after disconnected from power, maybe will be ok later. I thought it could be bottom connection issue.
After moved iMac into a quiet room, I heard buzzing noise from top left corner, I started believe the power supply got issue.
Replace power supply later together with fan.
IMAC Buzzing Noise From Top Left Corner FIXED!! / Replace Power Supply
Refering to some YouTube video, I tried to repair my iMac 27" (Mid 2011) Video Card, because my iMac could not boot and only apple logo appears. Steps as below
| Information | |
|---|---|
| Identifier | iMac12,2 |
| Model | A1312 (EMC 2429) |
| Family | iMac (27-inch, Mid 2011) |
| CPU | 3.4 GHz Intel Core i7 |
| Graphic | AMD Radeon HD 6970M 2048 MB |
Use sucker to take it out.
Got 8 screws.
The video card to LCD screen cable damaged, bought new one, waiting for delivery.
Oct 13, After purchased cable, replace it, works immeditially, then continue OS reinstallation.
Due to this machine is too hot, I think better only use it in aircon room, and no background service should be executed.
My iMac is different model as below, but similar.
A1312 iMac GPU Replacement
Late 2009 iMac 27" Video Card Repair — 4850 — 2nd Bake