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Current version by Craig Bender,

Title:

Boots, Fan runs fast, then black screen <<SOLVED>>
Boots, Fan runs fast, then black screen <<SOLVED>>

Text:

My computer starts up, all 4 LED lights are on solid green. After about 5 minutes the fan speed starts noticeably increasing. 5-10 minutes later the screen goes black and the #4 LED goes off, leaving LED&#039;s 1 through 3 solid green. The iMac doesn&#039;t shut down and fan continues to run until I hold power button down to shut it down.
If I restart immediately, the screen lights up &amp; the same situation happens. If I wait for a while to reboot, it seems to cool down &amp; the fan speed is normal for about 5 minutes and the same symptoms repeat.
I have: held power switch down with power disconnected for 10 seconds, reset PRAM, installed a new HDD &amp; tried fresh install of Mountain Lion (only because had to get data off previous one).
Any help greatly appreciated!
iMac 24&quot; 2.8 GHz EMC No. 2134
&lt;&lt;Answer to question, Nothing happened before this starting iMac was working fine &amp; no electrical surge issues &gt;&gt;
**Problem Solved, I decided to take my iMac in to local repair shop, the replaced the video card for $250. Unfortunately they didn't Zap the PRAM so I kept getting error messages when trying to install Lion or Mountain Lion, but after zapping PRAM work great. Thanks very much for the replies !!!

Device:

iMac Intel 24" EMC 2134 and 2211

Status:

open

Edit by Craig Bender,

Title:

Boots, Fan runs fast, then black screen

Text:

My computer starts up, all 4 LED lights are on solid green. After about 5 minutes the fan speed starts noticeably increasing. 5-10 minutes later the screen goes black and the #4 LED goes off, leaving LED&#039;s 1 through 3 solid green. The iMac doesn&#039;t shut down and fan continues to run until I hold power button down to shut it down.
If I restart immediately, the screen lights up &amp; the same situation happens. If I wait for a while to reboot, it seems to cool down &amp; the fan speed is normal for about 5 minutes and the same symptoms repeat.
I have: held power switch down with power disconnected for 10 seconds, reset PRAM, installed a new HDD &amp; tried fresh install of Mountain Lion (only because had to get data off previous one).
Any help greatly appreciated!
iMac 24&quot; 2.8 GHz EMC No. 2134
&lt;&lt;Answer to question, Nothing happened before this starting iMac was working fine.>>fine & no electrical surge issues >>
&lt;&lt;Answer to question, Nothing happened before this starting iMac was working fine.>>fine & no electrical surge issues >>

Device:

iMac Intel 24" EMC 2134 and 2211

Status:

open

Edit by Craig Bender,

Title:

Boots, Fan runs fast, then black screen

Text:

My computer starts up, all 4 LED lights are on solid green. After about 5 minutes the fan speed starts noticeably increasing. 5-10 minutes later the screen goes black and the #4 LED goes off, leaving LED&#039;s 1 through 3 solid green. The iMac doesn&#039;t shut down and fan continues to run until I hold power button down to shut it down.
If I restart immediately, the screen lights up &amp; the same situation happens. If I wait for a while to reboot, it seems to cool down &amp; the fan speed is normal for about 5 minutes and the same symptoms repeat.
I have: held power switch down with power disconnected for 10 seconds, reset PRAM, installed a new HDD &amp; tried fresh install of Mountain Lion (only because had to get data off previous one).
Any help greatly appreciated!
iMac 24&quot; 2.8 GHz EMC No. 2134
<<Answer to question, Nothing happened before this starting iMac was working fine.>>

Device:

iMac Intel 24" EMC 2134 and 2211

Status:

open

Edit by ABCellars,

Title:

Boots, Fan runs fast, then black screen

Text:

My computer starts up, all 4 LED lights are on solid green. After about 5 minutes the fan speed starts noticeably increasing. 5-10 minutes later the screen goes black and the #4 LED goes off, leaving LED&#039;s 1 through 3 solid green. The iMac doesn&#039;t shut down and fan continues to run until I hold power button down to shut it down.
If I restart immediately, the screen lights up &amp; the same situation happens. If I wait for a while to reboot, it seems to cool down &amp; the fan speed is normal for about 5 minutes and the same symptoms repeat.
I have: held power switch down with power disconnected for 10 seconds, reset PRAM, installed a new HDD &amp; tried fresh install of Mountain Lion (only because had to get data off previous one).
Any help greatly appreciated!
iMac 24" 2.8 GHz EMC No. 2134

Device:

iMac Intel 24&quot; 2.8 GHz EMC No. 2134 and 2211
iMac Intel 24&quot; 2.8 GHz EMC No. 2134 and 2211

Status:

open

Original post by Craig Bender,

Title:

Boots, Fan runs fast, then black screen

Text:

My computer starts up, all 4 LED lights are on solid green. After about 5 minutes the fan speed starts noticeably increasing. 5-10 minutes later the screen goes black and the #4 LED goes off, leaving LED's 1 through 3 solid green. The iMac doesn't shut down and fan continues to run until I hold power button down to shut it down.

If I restart immediately, the screen lights up & the same situation happens. If I wait for a while to reboot, it seems to cool down & the fan speed is normal for about 5 minutes and the same symptoms repeat.

I have: held power switch down with power disconnected for 10 seconds, reset PRAM, installed a new HDD & tried fresh install of Mountain Lion (only because had to get data off previous one).

Any help greatly appreciated!

Device:

iMac 24" 2.8 GHz EMC No. 2134

Status:

open