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Old Dec 24, 2012, 04:59 PM   #1
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Intel C2D iMac 24" Suspected Power Supply => Help converting to ATX PSU

Hi Guys,

I am new to this forum and unfortunately I found it due to a hardware problem with an iMac Core 2 Duo T7400 2.16 GHz which I bought recently.
I suspect it might have a problem with the psu and if that proves to be the case, I will consider converting it to an ATX PSU.
It only boots up if I warm up the PSU area with a hairdryer, otherwise it just starts for a few seconds and then no display but the fans are still running.
At the moment it runs Windows 7 Ultimate x64 because I was unable to install MAC OS X 10.6 because it was always shutting itself off during the final step of the install.
Once W7 was loaded, I have monitored the temperature of the system and the PSU was idling at ~64C and I was also experiencing high latency which made it unstable. I have disabled the internal WIFI card (installed an external USB WIFI card) and the temperature of the psu decreased to 50C and the latency came down within the limits and I believed everything was good but I was wrong.
During any demanding application (e.g playing HD movies) it was shutting off as explained above. The best thing I have managed to do to keep it running for a long period of time (approx 8 hours) until turned itself off again was to downclock the CPU using CPUGenie to 1.86 GHz with a voltage of 1.050V. During this 8 hours I did some short 10 min Prime95 tests, watched HD movies, youtube etc.
With all the tweaking I still have to warm it up with the hairdryer for 1-2 min after it gets to the room temperature in order to get it going.
Do you guys think it might be the psu? I only have atx psu's around the house and I can't check with a different one.
Or it could be the motherboard?
I only found documentation to install a atx psu in a G5 with 18pin connector. Mine has a 12pin as in the picture below but I can't find the pinout diagram for this particular model to start messing with it.

Thanks guys in advance for all your answers and sorry for the long post.

P.S: I have searched the forum for something similar but nothing showed up.
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