black screen iMac 21.5 (2010)

[diddi969]

Hi everybody,
Iam new here in the forum with a very big problem.
I hope anyone can help me.

My Imac 21.5 (2010) has a black screen.
I already checked smc / pram.
On external everything works but the internal display is not detected.
On my Macbook via displayshare it shows that there is no Display installed.
I opened the iMac and found out that the 4.th diagnostic led is not on.
Although I measured no voltage at the testpoint - enable backlight?!
...
I red a lot about led board but on screen there is absolutely nothing so I don't think it is, or am I wrong?
Are there any other measurepoint which I can check to determine the faulty part?

May aonyone knows what that can be.
THanks a lot for tips!!!
Sorry for bad english

 

[pcs123]

Black Screen iMac 21.5

Hi,

I have 2 iMacs here with exactly the same problem.

So far we changed everything except the logic board. On one of the machines it would initially display the Apple logo on boot and then switch to external display - after a PRAM reset it stopped displaying to the internal monitor altogether.

Did you ever find an answer?

If I find one I'll let you know.

Kind regards

Shaun Clarke

Hi everybody,
Iam new here in the forum with a very big problem.
I hope anyone can help me.

My Imac 21.5 (2010) has a black screen.
I already checked smc / pram.
On external everything works but the internal display is not detected.
On my Macbook via displayshare it shows that there is no Display installed.
I opened the iMac and found out that the 4.th diagnostic led is not on.
Although I measured no voltage at the testpoint - enable backlight?!
...
I red a lot about led board but on screen there is absolutely nothing so I don't think it is, or am I wrong?
Are there any other measurepoint which I can check to determine the faulty part?

May aonyone knows what that can be.
THanks a lot for tips!!!
Sorry for bad english