Very confusing issue with iMac 5k resolutions

[pigoo3]

The screen i have replaced it with must be a slightly different screen/model which they have started using since late 2015. For whatever technical reasons my late 2014 iMac can only run this screen at 4k...

So my next step is to find out what the model number of my broken screen was so i can source that exact replacement.

Sounds like this get's us back to the question asked earlier in the thread...do we have the correct part. Seems like you've come to the conclusion that the display panel purchased is not the correct part.

Does anyone know of any sites where i could find out exactly what the part number for it is ? perhaps somewhere which lists the components of every generation of iMac ?

This is one site I go to for parts info:

www.powerbookmedic.com

HTH,

- Nick

 

[moosed]

Ok well, things just got super confusing... I got the part number of my old screen and it's the same part number as the new screen.

LM270QQ1 SDA2

I have literally no idea where to go from here now :/

 

[pigoo3]

If:

- Got the right part.
- It was installed correctly.
- Did fresh install of the OS.
- Tried the resets suggested earlier.

Then it's almost got to be a settings issue. Have you absolutely tried adjusting the settings in Display Preferences...to the default settings?

Or there are details that haven't been shared that could be important. Please don't ask what these may be (we have no idea). Sometimes folks forget to share important details.

- Nick

 

[moosed]

My only doubt left with regard to it being the wrong part is if the ebay company sent me the wrong screen to the one listed, but im fairly certain they sent the correct one. I never bothered to actually check the label on it to see, just assumed it was correct as it looked correct.

Is there anyway i can find out what the screen is without taking it off ? perhaps some kind of terminal command ?

I found this:

ioreg -lw0 | grep IODisplayEDID | sed "/[<]*</s///" | xxd -p -r | strings -6

But it only reports what i think is a serial, and when i google that serial nothing of any relevance appears.

I really don't want to have to take the screen off to check, especially as im 95% certain its the correct part.

I have now done fresh installs of El Capitan and Sierra and the issue remains, the monitor is reported as 3840x2160 in 'about this mac' but is listed as 5120x2880 in system information.

If it's a setting issue then surely that would have been sorted by doing these fresh installs ?

I feel like im the only person in the entire world who has had this issue. There is nothing on google about it at all. Frustrating.

 

[moosed]

I wonder if i took it to an authorised apple repair centre if they'd take a look and see if they can figure it out ? do they do that ? obviously it would be a paid service... but are they happy to troubleshoot issues on macs which have had user modifications (ie: me replacing the screen) ?

 

[pigoo3]

If it's a setting issue then surely that would have been sorted by doing these fresh installs ?

Probably + doing the NVRAM Reset should return everything to their default settings.

Final thoughts on this:

With the info given...seems to me the trouble is one of the following:

1. There's a Display Preferences setting that's not being set properly (possible...but doubtful). Please double-check that you've tried all display preference options.
2. The correct part was purchased...but the part is faulty in some way.
3. The incorrect part was purchased...but was labeled as the correct part.

If it's the incorrect part or the part is faulty. We can continue with this discussion till we are blue in the face...and nothing will change.

If you feel that everything on your end (what you've tried)...has not ended with success. I would do my best to return the part. Somewhere...something just isn't right.

- Nick

p.s. Are you "Slack Panda"? If so...found your post on iFixit.com.

p.p.s. One "x-factor" or unknown detail that hasn't been considered in this discussion...is if during the process of damaging the display...maybe additional internal damage occurred. This is probably unlikely...but something that must be considered if everything else is correct (proper part, part is 100% operational, part was installed correctly).

 

[pm-r]

I'm just wondering if trying out using SwitchResX might help clarify or fix the problem??
At least its free to try and has sure helped other users with various Mac display resolution problems:
http://www.madrau.com




- Patrick
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