Very confusing issue with iMac 5k resolutions

[moosed]

So my 5k iMac screen got cracked/smashed so I ordered a new one to fit myself as the computer is out of warranty.

I've attached it and its working but when i click on the Displays setting in 'About this mac' it says that its 3840x2160 ?

However when i go to resolution settings the max available scaled resolution 'looks like 3360x1890'

However when i go to the system information screen it says its a 5k display...

On top of this when i click on the 'default resolution for this display' checkbox it switches it to 'looks like 1080p', however when i click the 'default' scaled tile icon it 'looks like 3080x1692'.

Anyone have an idea what could be going on ? Im bemused. My previous screen always had a default resolution which 'looked like 2560x1440' however now that resolution is no longer default and is seen in OSX as a scaled resolution. Why is mine defaulting to 'looks like 1080p' ?

If it's not the 5k screen (I'm fairly sure it is) why is it listed in system information screen as 5k ?

Have I encountered some weird kind of software glitch whilst swapping the screens over ?

Any help would be greatly appreciated.

Regard

 

[moosed]

FYI this is the screen i got

http://www.ebay.co.uk/itm/27-Apple-...571f42f&pid=100290&rk=1&rkt=1&sd=141853467305

Pretty sure its the correct one as mine is late 2014

edit: where did my original post go ?

 

[pigoo3]

Were you able to compare part numbers & and all other physical attributes of the old & new display panels?

For starters. If part #'s didn't match...or at least could not be cross referenced to match...then I would suspect maybe the panel is not correct. Just a theory...since this was not mentioned.

- Nick

 

[pigoo3]

edit: where did my original post go ?

As far as I can tell it's all there.

- Nick

 

[moosed]

Hmm, i can't see my original post for some reason.

I was not able to compare model numbers but this monitor is a 5k monitor as far as i can see... it's meant to be the correct one for all late 2014 5k iMacs and it's listed as 5k in the system information screen.

Google searches also suggests there is only 1 display available for it.

Why would it have different scaling options to the previous one if they are both 5k ?

So confused.

 

[harryb2448]

You need to be able to find out the precise part number you vare replacing..

Apple uses and re-uses model numbers. Now this may shock you. The model No. A1419 applies to the late 2013 27" iMac, the late 2014 27" iMac, the mid 2015 27" iMac, and for good measure the late 2015 27" iMac.

 

[pigoo3]

Hmm, i can't see my original post for some reason.

Did your original post contain 3 images? If so...that's the first post in the thread I see.

I was not able to compare model numbers but this monitor is a 5k monitor as far as i can see... it's meant to be the correct one for all late 2014 5k iMacs and it's listed as 5k in the system information screen.

It's always a great idea to compare the new part with the old part...just to be sure. More than likely you do have the correct part. Since (also more than likely) it woudn't fit properly or connect internally properly if it was the incorrect part.

Here's what I would suggest:

1. Do an SMC Reset:

https://support.apple.com/en-us/HT201295

2. Do an NVRAM Reset:

https://support.apple.com/en-us/HT204063

See if this helps.

- Nick

 

[pigoo3]

Do you still have the old part?

- Nick

 

[chscag]

Did your original post contain 3 images? If so...that's the first post in the thread I see.

His post with the images was moderated which is why you could see it and he couldn't. I just approved it and now should be visible to him also.

 

[moosed]

I got a shop to change it over and they may still have the broken screen. I'll get in contact with them to see if they still have it.

Regardless of this though... shouldn't all 5k screens have the same scaling settings/resolutions ?

Is it known that different generation 5k iMacs (there has been two of them correct ?) have had different scaled resolutions ? It's just weird that it thinks my default should be 'looks like 1080p'... that's what id expect of a 4k screen, but this is definitely 5k as shown in the system information screen.

Bizarre.

Anyway i'll get back to you guys once i've phoned the shop.

Appreciate the help.

 

[pigoo3]

I got a shop to change it over and they may still have the broken screen. I'll get in contact with them to see if they still have it.

The first post says "fit myself as the computer is out of warranty". When someone says this...I assume they are actually doing the replacement themself. If a local non-Apple shop did the work...then the shop did the repair.

Thanks for clarifying.

Regardless of this though... shouldn't all 5k screens have the same scaling settings/resolutions ?

Here is a curious detail I came across. If you go to Everymac.com...and look up the spec's for this model (27" 5k iMac Late 2014):

http://www.everymac.com/systems/app...-inch-aluminum-retina-5k-late-2014-specs.html

You will see that the native resolution of the internal display = 5120 x 2880. Maximum resolution for an external display = 3840 x 2160. Exactly what you're seeing in the "About This Mac" info in image #1 above. A curious coincidence. Maybe the computer thinks this is an external display (just a thought).

- Nick

p.s. Did you try the two resets I mentioned?

 

[moosed]

The first post says "fit myself as the computer is out of warranty". When someone says this...I assume they are actually doing the replacement themself. If a local non-Apple shop did the work...then the shop did the repair.

Thanks for clarifying.



Here is a curious detail I came across. If you go to Everymac.com...and look up the spec's for this model (27" 5k iMac Late 2014):

http://www.everymac.com/systems/app...-inch-aluminum-retina-5k-late-2014-specs.html

You will see that the native resolution of the internal display = 5120 x 2880. Maximum resolution for an external display = 3840 x 2160. Exactly what you're seeing in the "About This Mac" info in image #1 above. A curious coincidence. Maybe the computer thinks this is an external display (just a thought).

- Nick

p.s. Did you try the two resets I mentioned?

Hello. That is curious... should that screen show 5120x2880 ? can any iMac 5k users check and confirm what their resolution is listed as in 'about this mac>displays' ?

and yes I tried the two resets you mentioned but no luck with either.

 

[moosed]

Just did a fresh install of operating system. Issue still remains

Sigh

 

[moosed]

another bit of weirdness... now when i go to the overview page via 'about this mac' it just says 'iMac' whereas previously it said something like 'iMac late 2014'

 

[pigoo3]

What OS version are you installing?

How did the display get smashed?

- Nick

 

[moosed]

I am using latest version of Sierra

The display got hit by a guitar head (its setup in music studio), just the edge was cracked but im fussy and wanted the computer looking as new and thus got the replacement.

 

[moosed]

I think i've just sussed it out

I found this in a listing for my display

if your model is 5K Late 2015, it is 100% compatible with LM270QQ1 SDA2.
if your model is 5K Mid 2015 or Late 2014, The maximum resolution is 4K.

Doh ! and yet its listed as 5k in the system information. I guess for some bizarre reason it's not supported to display at that resolution

 

[pigoo3]

I think i've just sussed it out

I found this in a listing for my display

if your model is 5K Late 2015, it is 100% compatible with LM270QQ1 SDA2.
if your model is 5K Mid 2015 or Late 2014, The maximum resolution is 4K.

Doh ! and yet its listed as 5k in the system information. I guess for some bizarre reason it's not supported to display at that resolution

I'm not so sure about that.

Default resolution should be 5120 x 2880...5K (should say this in the "About This Mac" info area...and in the Display Preferences area).

For a 2nd external display connected to the iMac...maximum resolution for it is 3840 x 2160. This is called 4K Ultra HD.

Here's a couple review articles for the Late 2014 27" 5K iMac which definitely mention the 5K resolution (5120 x 2880).

https://www.engadget.com/products/apple/imac/27-inch-with-retina-5k-display/late-2014/
http://www.macworld.com/article/284...isplay-is-among-apple-s-brightest-lights.html

HTH,

- Nick

 

[moosed]

I'm not so sure about that.

Default resolution should be 5120 x 2880...5K (should say this in the "About This Mac" info area...and in the Display Preferences area).

For a 2nd external display connected to the iMac...maximum resolution for it is 3840 x 2160. This is called 4K Ultra HD.

Here's a couple review articles for the Late 2014 27" 5K iMac which certainly mention the 5K resolution (5120 x 2880).

https://www.engadget.com/products/apple/imac/27-inch-with-retina-5k-display/late-2014/
http://www.macworld.com/article/284...isplay-is-among-apple-s-brightest-lights.html

HTH,

- Nick

Hey

I think your misunderstand.

My previous screen which broke supported the 5k, it worked and displayed at the correct resolutions, everything was fine.

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.

I had previously researched to see if their were multiple different displays available but only ever found one part, thus I presumed it must be the correct one. Seems i was wrong and there are more 5k retina screens which were used in iMacs.

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 ?

 

[chscag]

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...

Too late now but our recommendation is always let Apple do the repairs even if the broken screen was not covered under the warranty. They would have used the correct part which probably would have cost you more at first but you would have had a warranted repair on the new screen. (90 days) Now you're likely going to spend more trying to get the correct display.