Chosen Solution
I have a 27 inch iMac type EMC 2429 on which I have exchanged the video board After reassembling the system the fans started making a lot of noise. After taking off the screen again, I noticed that there is one connector missing. It is not attached to the mainboard. Before I start taking the mainboard out, I want to know which connector is missing. I have a picture of the board and where the connector should be. (See picture with circle mark on the connector).
Please let me know if you know what connector this is and where the fitting cable should be. Update (02/12/2019) You certainly have an eagle’s eye Steve!
So, you were right about that two-wire connector, of which the white wire was disconnected. I solved that by pushing it in again and squeeze it for contact by pushing a thin needle alongside. Restarting the system did not solve the fan issue. It started blowing again at high speed within 20 or 30 seconds after power up. What I also noticed is that the black flat cable (see picture) connecting the screen to the main PCB is damaged on the connector that goes into the connector holder on the main PCB. I think I have to replace that.
Two questions now:
- Could that damaged flat cable cause the fans to run at high speed?
- In my earlier post I referred to a connector position, which is empty. At least I did not find a connector that should go in there. Is this one to remain empty, or did I mis a connector that should be there?
That is a diagnostic connector and is not your problem. Using your picture as reference, look closely at the two-wire connector to the left of your red circle (to the immediate left of “RGT SKIN” on the motherboard). That’s your thermal sensor, and if you look closely you’ll see that the white wire has been partially pushed out of the connector which means your computer isn’t getting a reading from that sensor and as a failsafe has put the fans on at full speed. Unplug the connector, carefully slide the wire back into place, plug it back in, and your problem should go away.
