Orange gradient on screen after reassembling an iMac

[Juperio]

Hello,
I recently had graphic card issues (green pixels, freezing, etc.) on my iMac 21.5 mid-2010. I have just replaced the graphic card with a new one bought on eBay (same model as the original). Everything works fine except that I now have a slight orange tint on the lower part of the screen. It’s like a soft vertical gradient that is quite homogenous across the screen (see picture below).

The orange tint is not visible on screenshots so I assume it isn't the new graphic card that is at fault but the screen.

I was wondering what could be the cause and if there’s any way to fix it?

I carefully remove the screen following the instructions on this tutorial and left the screen standing against a wall with the screen protection on it while replacing the graphic card. Could it be something I did wrong when reassembling the Mac? Any ideas?

 

[chscag]

I was wondering what could be the cause and if there’s any way to fix it?

Looks like dirt or dust has clinged to the screen when you disassembled the machine. It's caused by static electricity. You need to take it apart again and clean the screen with anti-static fluid and cloth.

 

[pm-r]

Looks like dirt or dust has clinged to the screen when you disassembled the machine.

I would say that chscag has given you the answer that you need as it seems that model is using the LED backlighting and not the florescent lightning that the older iMacs used that could produce a similar color cast.

2010 21.5-inch (viewable) uses LED-backlit glossy 16:9 widescreen TFT active-matrix display, IPS technology.

They actually make rollers with special adhesive that will pick up and remove any tiny piece of dust when cleaning the Monitor display glass. It depends on how fussy you want to get, but you could probably do very well with a good glass cleaner and a good lint-free microfibre cloth in a very clean and dust-free area.



- Patrick
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[Juperio]

Thanks for the input.
I used a manual dust blower to remove as much dust as possible. Seems like it wasn't enough. Will try your solution.

 

[chscag]

Don't use a dust blower as that creates static electricity and will cause more dust to eventually accumulate. You need to remove the screen and use anti-static solution and a anti-static cloth. Apply the solution to the cloth, do not spray it directly on the screen. Good luck.

 

[pm-r]

use anti-static solution and a anti-static cloth. ...

That is a good practical suggestion, Charlie. And both products are readily available.



- Patrick
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[chscag]

One thing about his model iMac which is nice is that the glass and screen are separate items and not glued together as are the later models.

The only problem with that setup is dust and dirt can get between the glass and screen. And since iMacs draw air in from the bottom vents below the screen it's easy for dust to get caught up. That's one reason why Apple decided to glue the glass and screen together in later models.

The way Apple has been using glue lately leads me to believe they own glue manufacturing stock!