Black Internal LCD issues (while external monitor works)
I write this post to summarize the issue I faced. This is a hardware issue.
iMac 27" late 2009
iMac 27" 2010
Issue: Black internal screen while external monitor displays image well. Backlight does work, confirming by the glow under the screen change when I tried changing the backlight level.
Cause: knocked off component on the logicboard. This occurred when I shaked the heatsink to remove the MXM card.
Location of the component: 3cm above the bottom right conner of the heatsink frame. (Mark Q9001)
(I will upload my photo later, or you can see details in
this thread )
Component: 2N7002k (the mark on the component will be k72.., where the dots are replace with letter to indicate year and month of production). Some say it's a transistor, some say it's a mosfet. I think it's a transistor. It's sold on Aliexpress at 1$ for 100 units, plus shipping.
I bought 20 from a local shop for 3$ (faster delivery) and brought both of my IMacs to a cellular phone repair shop to get them soldered to the logicboard. He charged me 2.5$ for the fix.
Hope this info help those who were lazy and reckless like me.
How to prevent knocking off this component again: Insert a hard plastic card (bank card, etc.) under the metal frame before shaking the MXM card out of its position.
Or do it right by removing the whole logicboard from the case when changing the graphic card.
iMac 2011 doesn't got this issue because the MXM card cannot be removed without taking out the whole logic board out first.
