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Mid-2007 iMac CPU Fan Shot?

powerbook911

powerbook911

macrumors 601
Original poster
Mar 15, 2005
4,009
398
My Mid-2007 iMac keeps on performing. 20-inch 2.4 GHZ.

However, I noticed recently that the Geek Bench scores were dramatically lower, i.e. 20 percent lower than the average. However, if I shutdown the computer for one hour, the scores were well above average.

I immediately thought this could be temperature related.

I downloaded Mac Fan Control and it is reporting 0 RPM on the CPU Fan. If I manually control it, it stays at 0.

I wonder if the fan is shot, or if dirt could clog it to the point it stops?

Obviously I need to open it up, sadly my tools and suction cups are probably lost from when I did the hard drive replacement in 2010.

Still, I wanted to make sure I wasn't overlooking something first, such as the CPU fan being unreadable on 2007 iMacs or something?

Thanks.
 
dyt1983 said:
Even if it is unreadable, doesn't your other evidence point to something being wrong that you need to open it up? ;)

Dirt clog, broken fan, etc.
Click to expand...

Thanks.

I went ahead and did it today. I did not enjoy it. ha-ha. Well, maybe a little. So many screws, and then putting the glass back on, it takes about 20x to get it lint free, and the bottom tab that inserts into a hole broke, but it doesn't affect anything. I kept leaning it against that one while dusting between the inside glass, so it snapped that. I hope this won't cause me an issue if I decided to put in a SSD later on. Took a good 90 minutes total with all the screen cleaning.

To the fan, it didn't look THAT bad. A light dust coating, though the connector was really covered that plugs into the logic board I guess.

I went ahead and fully removed the fan, to blow it out and whatnot. Plus made sure the connector area was clean.

I had no faith this could fix it.

However, started machine up, instead of 0 RPM on CPU fan, fan was running at 1200 and Geekbench scores and Cinebench scores are high again (relative to Geekbench averages for this machine).

Wow. Fixed, I hope.
 
I've had fans with dead spots that will start and stop intermittently. It's better to replace it, rather than having to go through disassembly all over again. It's probably a $10 part.
 
senseless said:
I've had fans with dead spots that will start and stop intermittently. It's better to replace it, rather than having to go through disassembly all over again. It's probably a $10 part.
Click to expand...


I'll keep an eye out then. Good to know. However, it was 100 percent not working for a couple weeks I think.

Plus, since I was opening it today with no replacement in hand, I really didn't have any other option. At least I got it working for now and know what it is.

However, this is really good information so I can know to keep an eye out.

I appreciate it, I have my fingers crossed it might be ok.

Funny thing, the person who primarily uses it in the house now, checks email and uses word, so even with no fan, it wasn't forcing shutdowns or whatnot, and it is turned on 24/7.
 
senseless said:
I've had fans with dead spots that will start and stop intermittently. It's better to replace it, rather than having to go through disassembly all over again. It's probably a $10 part.
Click to expand...

HI senseless

You were right. I kept checking the fan RPM this past week when I think of it.

Checked it again today, and the fan is reading 0 RPM again and temps are high.

Funny thing, there is no way to make it run again either, it just stays off.

I took a picture of the fan so hopefully I can find the part cheap, though it's bit old machine.


Update -

I only see used fans, hate to get one that has this same problem, but I guess thats what it is.
 
Last edited:
I ended up paying about $7.00 with shipping for a used fan. It had the slightly newer part number than the one on my original fan from the 2007 machine.

I replaced it, only took 40 minutes tops this time after the 90 minutes I spent simply cleaning the machine out a couple weeks back.

I won't hold my breath too quickly because it took two weeks for the fan to stop working again last night, but with a replacement, I'm optimistic the machine will be good to go now.

Thanks for all the advice along the way. It's nice to think a little time and a few dollars might keep this machine going.
 
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