Black screen doesnt show anything..

When I press Start Button it gives the chime, but nothing comes to display.

Out of four LEDs on the motherboard the fourth one is off. Rest three are working.(the fourth one is of the LCD panel).

The fans are working fine.

The LVDS cable looks fine. Every thing looks fine , except the display.

There is nothing on the screen even when i try to see by placing a torch near the lcd manel.

I replaced the inverter with another mac’s inverter , still the same problem remains.

It seems the imac is working , because the fans are working, it is giving a chime on start, but the screen is not showing anything .

When I connect external screen with minidisplay , it displays a message insert a bootable device and press any key.(because i have formatted the hdd )

Please suggest me what could be the problem and ways to reapir it.

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5 commentaires:

Can you give us the history on what happened to the system. Was it dropped or banged? Where you doing an upgrade or cleaning the system and it didn't work afterwards?

What happens when you plug in an external monitor?

par

Since the model you posted does not have an inverter, let see if we can correctly identify it. Look on the bottom of the stand, then tell us exactly what you have.

par

@danj

it was working fine. when i turned it on next day, it gave a chime and nothing displayed. I tried all quick fixes, but noting workd. So i took out th hdd and put it in another imac . the second imac booted with the first one hdd , and worked fine. So i formatted the hdd using a sata cable with the help of my pc.

now tthat I have put the hdd and tried to boot it through a usb bootable mac os, it doesnt boot.

So this time I connected an external screen . The screen was working but , it shows a message insert a bootable device and press any key to proceed, after 5 min of start of the system.

I opened my imac apart and looked for the led lights on the motherboard.

The fourth one was not lit, other three were lit.

I looked on internet to confirm which led light was it. It was the lcd light.

Please suggest me the possible sol;ution for this , and what could the reason.

par

@mayer

This model has a lcd backligh INverter.

It is a1311

EMC 2428

par

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