Model A1311 / Mid 2010 / 3.06 & 3.2 GHz Core i3 or 3.6 GHz Core i5 Processor

231 Questions View all

Screen blank, LED status lights #1 and #2 are on -New Question!

Model A1311 IMac Intel 21.5" EMC 2389

(PAST) I picked up this Imac for cheap (free) and thought I would give it a go to repair it. The first and second lights of the four status lights are lit which makes me think it is the video card or logic board itself...any suggestions on narrowing it down if this is the case and where/how much replacing them would be?

Answered! View the answer I have this problem too

Is this a good question?

Score 0

Comments:

Ok...so here is an update of where I am at. I replaced the CPU with a I3-550 and got the third LED Diagnostic Light to come on but the screen still isn't coming on. I connected an external display via a mini displayport to hdmi adapter (which by the way there seems to be a lot of trouble with these, so I tried the vga adapter and the external now works. It looks like now I need to replace either the internal displayport cable or the LCD itself.

by

I have ordered a new display port cable as per the troubleshooting I have seen done on the internet and still I have no display. I am not getting the back lights to turn on or anything image on the screen as far as I can tell. There still seems to be something wrong with the logic board in my opinion. Any one else have any insight...I have seen things about the vertical sync cable, the display cable, the temperature sensor...not sure where else to go.

by

Ok...I am back...I had a friend loan me his imac and I tested his display on my computer...it didn't work...I tested my display on his computer and it worked. I am narrowing it down to the logic board but not sure I can even repair the board without just doing a complete replacement. Anyone come across this?

by

Add a comment

1 Answer

Chosen Solution

Plug in an external monitor to test the GPU.

LED #1

Indicates that the trickle voltage from the power supply has been detected by the main logic board. This LED will remain ON whenever the iMac is connected to a working AC power source. The LED will remain on even when the computer has been shut down or put to sleep. The LED will turn off only if the AC power source is disconnected or the power supply is faulty.

LED #2

Indicates that the main logic board has detected proper power from the power supply when the computer is turned on. This LED will be ON when the computer is turned on and the power supply is working correctly.

LED #3

Indicates that the computer and the video card are communicating. This LED will be ON when the computer is communicating properly with the video card. If LEDs 1 and 2 are ON and you heard the startup sound, but LED 3 is OFF, then the video card might be installed incorrectly or need replacement.

LED #4

Indicates that the computer and the LCD display panel are communicating. This LED will be ON when the computer is turned on and video signal is being generated. If the LED is ON and there is no image on the LCD display panel, the LCD display panel or inverter might be installed incorrectly or need replacement.

Was this answer helpful?

Score 1

Comments:

I am not sure I hear the startup sound but I eill try the external monitor.

by

Tried the external screen and nothing happened. Is this the logic board that needs replaced then? Would a bad hard drive prevent startup?

by

Ok...so I took a chance based on another person's success and replaced the CPU with an I3 550. I now hear the chime on start up and have LED's #1, #2, and #3 lit up but I still don't have a display? LED #4 is still not on...so any ideas?

by

Hook it up to an external monitor and see if a video signal is being generated.

by

No luck on an external monitor...sounds like a bad logic board maybe?

by

Show 7 more comments

Add a comment

Add your answer

Chad32 will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 0

Past 30 Days: 4

All Time: 447