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現在のバージョン作成者: Dan ,

タイトル:

Late 2015 iMac Black Screen with Chime but no #3 LED

テキスト:

I recently removed my iMac late 2015 i5 27” screen to upgrade the hard drive. (Something I’ve done successfully before). Upon re-assembly, the machine would not boot. Got a chime but then a full black screen.
I removed the screen again, checked all of the connections, and they seem good. I get LED #1+#2 lit up on the diagnostic, but no #3. I’ve read that this means the the video card and logic board are not communicating.
I’ve tried resetting the PRAM and the SMC with no luck.
* Questions:
** Are there any further suggestions about what to try to get it running again?
** Is there any value in pulling the whole thing apart to replace the PRAM battery? I read one place this could be a fix, but it seems like a lot of work if it’s a dead end.
Thanks for any help.
=== Update (03/16/2021) ===
I took the entire iMac apart to replace the PRAM battery. This did not help, but it was a ton of work.
Still getting only LED#1 and LED #2 lit up with a chime and a black screen.
I DID plug into an external display that that WORKS. I put some fan monitoring software and got the following showing no fan sensor for the LCD Flying Lead.
[image|2356455]
I assume this is the thermal sensor monitor on the display. Either it’s damages or disconnected.
Does anyone know if THIS is the sensor?
[image|2356460]
AND does it seem like this might be a solution to getting this machine up and running again. I don’t want to quit on it!
Thanks
=== Update (04/23/2021) ===
I’m throwing out one last request for help with this machine. (Late 2015 iMac)
I have scoured the forums here and elsewhere and have tried every single thing I’ve found short of replacing the logic board. Are there any other ideas before I have to strip this iMac down and sell it for parts?
-'''Summary of the problem:'''
+***Summary of the problem:***
-'''Symptoms:'''
+***Symptoms:***
* Screen stays black
* Fans go at full speed
* Computer boots and work with an external monitor, although throttled down due to fan issue
* Flying Lead Sensor still doesn’t show up in iStats.
-'''Repair attempts:'''
+***Repair attempts:***
* Replaced LVDS Cable
* Replace PRAM Batter
* Reset PRAM and SMC
* Replaced screen with know working screen (symptoms were exactly the same)
* Replaced the thermal sensor cable on the back of the LCD panel.
* Fully removed all internals are replace to check every cable connection was firm.
* Ran Apple Hardware test got these results:
** There may be an issue with the System Management Controller (SMC). Reference Code: PFM006
** There may be an issue with the display. Reference Code: VFD001
Anybody here have any further ideas for a fix?
Thank so much in advance.

デバイス:

-iMac Intel 27"
+iMac Intel 27" Retina 5k Display

ステータス:

open

編集者: Eric Bryant ,

タイトル:

Late 2015 iMac Black Screen with Chime but no #3 LED

テキスト:

I recently removed my iMac late 2015 i5 27” screen to upgrade the hard drive. (Something I’ve done successfully before). Upon re-assembly, the machine would not boot. Got a chime but then a full black screen.
I removed the screen again, checked all of the connections, and they seem good. I get LED #1+#2 lit up on the diagnostic, but no #3. I’ve read that this means the the video card and logic board are not communicating.
I’ve tried resetting the PRAM and the SMC with no luck.
* Questions:
** Are there any further suggestions about what to try to get it running again?
** Is there any value in pulling the whole thing apart to replace the PRAM battery? I read one place this could be a fix, but it seems like a lot of work if it’s a dead end.
Thanks for any help.
=== Update (03/16/2021) ===
-
-
I took the entire iMac apart to replace the PRAM battery. This did not help, but it was a ton of work.
Still getting only LED#1 and LED #2 lit up with a chime and a black screen.
I DID plug into an external display that that WORKS. I put some fan monitoring software and got the following showing no fan sensor for the LCD Flying Lead.
[image|2356455]
I assume this is the thermal sensor monitor on the display. Either it’s damages or disconnected.
Does anyone know if THIS is the sensor?
[image|2356460]
AND does it seem like this might be a solution to getting this machine up and running again. I don’t want to quit on it!
Thanks
+
+=== Update (04/23/2021) ===
+I’m throwing out one last request for help with this machine. (Late 2015 iMac)
+
+I have scoured the forums here and elsewhere and have tried every single thing I’ve found short of replacing the logic board. Are there any other ideas before I have to strip this iMac down and sell it for parts?
+
+'''Summary of the problem:'''
+
+'''Symptoms:'''
+
+* Screen stays black
+* Fans go at full speed
+* Computer boots and work with an external monitor, although throttled down due to fan issue
+* Flying Lead Sensor still doesn’t show up in iStats.
+'''Repair attempts:'''
+
+* Replaced LVDS Cable
+* Replace PRAM Batter
+* Reset PRAM and SMC
+* Replaced screen with know working screen (symptoms were exactly the same)
+* Replaced the thermal sensor cable on the back of the LCD panel.
+* Fully removed all internals are replace to check every cable connection was firm.
+* Ran Apple Hardware test got these results:
+** There may be an issue with the System Management Controller (SMC). Reference Code: PFM006
+** There may be an issue with the display. Reference Code: VFD001
+Anybody here have any further ideas for a fix?
+
+Thank so much in advance.

デバイス:

iMac Intel 27"

ステータス:

open

編集者: Eric Bryant ,

タイトル:

Late 2015 iMac Black Screen with Chime but no #3 LED

テキスト:

I recently removed my iMac late 2015 i5 27” screen to upgrade the hard drive. (Something I’ve done successfully before). Upon re-assembly, the machine would not boot. Got a chime but then a full black screen.
I removed the screen again, checked all of the connections, and they seem good. I get LED #1+#2 lit up on the diagnostic, but no #3. I’ve read that this means the the video card and logic board are not communicating.
I’ve tried resetting the PRAM and the SMC with no luck.
* Questions:
** Are there any further suggestions about what to try to get it running again?
** Is there any value in pulling the whole thing apart to replace the PRAM battery? I read one place this could be a fix, but it seems like a lot of work if it’s a dead end.
+Thanks for any help.
-Thanks for any help.
+=== Update (03/16/2021) ===
+
+
+I took the entire iMac apart to replace the PRAM battery. This did not help, but it was a ton of work.
+
+Still getting only LED#1 and LED #2 lit up with a chime and a black screen.
+
+I DID plug into an external display that that WORKS. I put some fan monitoring software and got the following showing no fan sensor for the LCD Flying Lead.
+
+[image|2356455]
+
+I assume this is the thermal sensor monitor on the display. Either it’s damages or disconnected.
+
+Does anyone know if THIS is the sensor?
+
+[image|2356460]
+
+AND does it seem like this might be a solution to getting this machine up and running again. I don’t want to quit on it!
+
+Thanks

デバイス:

iMac Intel 27"

ステータス:

open

オリジナル投稿者: Eric Bryant ,

タイトル:

Late 2015 iMac Black Screen with Chime but no #3 LED

テキスト:

I recently removed my iMac late 2015 i5 27” screen to upgrade the hard drive.  (Something I’ve done successfully before).  Upon re-assembly, the machine would not boot.  Got a chime but then a full black screen.

I removed the screen again, checked all of the connections, and they seem good.  I get LED #1+#2 lit up on the diagnostic, but no #3.  I’ve read that this means the the video card and logic board are not communicating.

I’ve tried resetting the PRAM and the SMC with no luck.

* Questions:
** Are there any further suggestions about what to try to get it running again?
** Is there any value in pulling the whole thing apart to replace the PRAM battery?  I read one place this could be a fix, but it seems like a lot of work if it’s a dead end.

Thanks for any help.

デバイス:

iMac Intel 27"

ステータス:

open