The screen on my (desktop, not laptop) iMac is not working .. the backlight only works sporadically.

If I hold a flashlight up to the dead screen, I can see the pixels; the video is working, just not the backlight.

I've connected a second display (it is mirrored; both show the same desktop), so I can still use the computer.

The interesting thing is that if the computer "sleeps", upon being woken up, the iMac's display works briefly for a fraction of a second, then it goes dark again.

According to a sticker on the back of the panel, it uses CFL compact fluorescent lamps (not LEDs). The inverter is located on the mainboard (underneath the CD drive); the wires are soldered to that board.. the other ends are soldered directly to the CFL lamps.. but there are connectors in the middle of each wire.

BTW, the capacitors on the inverter board look OK, I don't see any burn marks, or broken wires, or bad solder connections on that board.

Does this sound like a problem w/ the inverter board, or with the connectors in the middle of the wires that go to the lamps?

EDIT: this is a 2008 iMac 20" 2.66/2x2g/320/wm/wk

  • Welcome to Ask Different! :) In order to ensure you get accurate advice, can you edit your question (there's an edit link below it) to add in the exact details of your model of iMac? Thanks! – Monomeeth Apr 14 '17 at 2:08

Try to reduce the screen brightness to minimum. Put the computer to sleep and wake it up.

Better (90%)?

--> e.g. https://www.youtube.com/watch?v=gSzmyqQFZ2M

Not better (10%) -->

Toast your graphics board in the oven

e.g. https://macman860.wordpress.com/2013/02/03/baking-a-graphics-card/

Better (90%) --> You're welcome

Not better --> New inverter board

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