black screen in iMac 21.5 Late 2012 13,1 Backlight

[elcheca1]

Today something very strange happened to me, I bought an SSD for the PCIe connection for the operating system and I left the HDD for files of the iMac Late 2012 21.5" (13.1)

But after testing the SSD already connected and working I even had catalina installed

When I restart the iMac I get a black screen but the iMac turned on normally because even with the black screen I can see the apple sign and I also see the image that I have at the time of placing the password when I log in

What could it be? What do you recommend, because apparently the screen is fine, it's just the light that doesn't appear

Thanks 🙏

 

[DeltaMac]

Do you mean that this was working (backlight and all) when you first tested it after everything was in place, and it simply never came up bright on the next restart? What a disappointment! (I service a lot of Macs, and I have been there, too.., and I also know what "fun" is involved with getting to that blade slot for the SSD)

So, not really a "black screen", as you can see the video, but no brightness on the screen.
I think there is a backlight circuit board on the backside of the display assembly.
Or, the brightness (the backlight) is controlled from a chip on the logic board.

Gets a bit expensive in a hurry...

But, as you have had it all apart already, you now know how to get inside. There's only two connectors to the display. I would suggest re-checking both of those. (the tape usually does not survive a re-opening, so you will need to re-tape after a successful test.) Maybe you will get lucky.

Finally, you don't have to repair this, as an external display should work just fine. Kinda takes away the value of an all-in-one --- but it's a direction that you could take.

 

[elcheca1]

thanks for your answer, another thing I'm thinking that it could be the Flex because sometimes I remove the screen and put it back and it turns on normally that happens sometimes not always

One person told me that it could be the MotherBoard connector that is damaged and I say no because I have a MotherBoard late 2013 here and I make all the connections and the same thing happens, I imagine it must be the flex

and like all inexperienced in the matter I would like to know if it is possible to get that flex or if someone knows the correct name of the flex to buy it
Thank you

 

[elcheca1]

Do you mean that this was working (backlight and all) when you first tested it after everything was in place, and it simply never came up bright on the next restart? What a disappointment! (I service a lot of Macs, and I have been there, too.., and I also know what "fun" is involved with getting to that blade slot for the SSD)

So, not really a "black screen", as you can see the video, but no brightness on the screen.
I think there is a backlight circuit board on the backside of the display assembly.
Or, the brightness (the backlight) is controlled from a chip on the logic board.

Gets a bit expensive in a hurry...

But, as you have had it all apart already, you now know how to get inside. There's only two connectors to the display. I would suggest re-checking both of those. (the tape usually does not survive a re-opening, so you will need to re-tape after a successful test.) Maybe you will get lucky.

Finally, you don't have to repair this, as an external display should work just fine. Kinda takes away the value of an all-in-one --- but it's a direction that you could take.

what do you think about this

 

[DeltaMac]

You CAN find separate cables on eBay - https://www.ebay.com/itm/254956894050

That link appears to be the video data cable. Did not find the other cable (display power), but I didn't take a lot of time... Maybe you can also search for it. (the data cable might be a fix, if it is used for the backlight control, IDK)

Just a comment (that you did not ask for) -- Those connectors are, IMHO, not designed for frequent access.
The cables attach to the matching connectors on the logic board (as you know), and can the board connectors can certainly be damaged through multiple connections. All it takes is for one of those tiny contacts to get moved out of position, or just barely touching, to leave you with an intermittent, or no connection. (I can speak of actual experience, taking a bunch of time with a lighted magifier and a microprobe, trying to re-align a couple of contacts on just such a ribbon cable connection, trying to fix something that I almost ruined. I was lucky that time... It happens!

 

[elcheca1]

You CAN find separate cables on eBay - https://www.ebay.com/itm/254956894050

That link appears to be the video data cable. Did not find the other cable (display power), but I didn't take a lot of time... Maybe you can also search for it. (the data cable might be a fix, if it is used for the backlight control, IDK)

Just a comment (that you did not ask for) -- Those connectors are, IMHO, not designed for frequent access.
The cables attach to the matching connectors on the logic board (as you know), and can the board connectors can certainly be damaged through multiple connections. All it takes is for one of those tiny contacts to get moved out of position, or just barely touching, to leave you with an intermittent, or no connection. (I can speak of actual experience, taking a bunch of time with a lighted magifier and a microprobe, trying to re-align a couple of contacts on just such a ribbon cable connection, trying to fix something that I almost ruined. I was lucky that time... It happens!

that ebay link you sent is the energy flex

suppose that this is the flex that I need, this is the one that goes to the MotherBoard

I would like to see more information about it because this may be the flex that sends the energy so that the screen lights up