Mini late 2009 kernel panics and AHT error code

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zruhlen

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I have a late 2009 Mini that has had kernal panic issues for some time. When I first bought the computer it had 1/120 and I upgraded it to 2/320 myself. It is hooked up to my HDTV as a media server and it started getting kernel panics running Netflix in Safari. Sometimes the fan would spin up to very high levels while running Virtual Box with Windows XP.

It seemed to be the added RAM and I pulled it. Panics went away but now it is very slow. I purchased 2 - 2GB RAM from OWC and installed in machine. It was good for a while but then started kernel panics again.

Recently my MS bluetooth keyboard started having issues connecting and the panics got worse. The other day on a restart from a kernel panic it just beeped at me while blinking the power light one time. I looked it up and the error code was no RAM installed. I restarted and the beep was gone and that's when I ran AHT. I ran AHT on the machine and got the following error code:
4MOT/2/40000004: Master - 0 I reran the test and got 4MOT/2/40000004: Master - some 4 digit number I didn't write down because someone unplugged the machine while I was getting a pen.

It appears to be heat related because after a kernel panic if I leave the machine turned off for half an hour or so it works again for a while but if I just restart it will panic again within the next 15 minutes.

Any help greatly appreciated
 
The 4MOT error is fan-related. The fan may not be turning fast enough for good cooling, or may not be working at all.
Are you saying that your mini originally came with one hard drive, and now has two internal hard drives? Did you replace the internal interconnect card with the correct one used with dual hard drives? That piece is different on the standard dual-drive mini.
 
DeltaMac said:
The 4MOT error is fan-related. The fan may not be turning fast enough for good cooling, or may not be working at all.
Are you saying that your mini originally came with one hard drive, and now has two internal hard drives? Did you replace the internal interconnect card with the correct one used with dual hard drives? That piece is different on the standard dual-drive mini.
Click to expand...

Also 2 drives are going to generate more heat then the Minis little single fan is designed to dissipate. You may have to run the machine with the lid off permanently to provide adequate cooling. Might also want to run a portable fan on it while the lids off. Especially if you are trying to do processor intensive things like run it as a media server.
 
Maybe I wasn't clear. I swapped out the 120GB hard drive for a 320GB 7200rpm one. There is only one drive in the machine. I downloaded SMCFancontrol and set the minimum fan speed to 2500rpm and that seems to be working right now. At least it didn't panic last night. We'll see how it does moving forward. I suspect that whatever is supposed to speed up the fan as the computer gets warmer isn't working correctly. SMC reports the temp and fan speed for me and both appear to be functioning correctly.
 
I found more info on Mac Mini heat issues so downloaded Fan Control and changed the fan/temp profile. Ran a stress test and it only hit 133f. The fan spun up as it should and I think this may solve my problem. On further reflection I think that since the Mini gets so amazingly hot before the fan kicks into a higher speed that my RAM is getting flaky at those temps. Others have reported similar issues with the Mini. Notable is that the fan doesn't speed up till a temp of 82C or so. That's just unacceptable. I know iSteve likes quiet machines but I kind of prefer working ones that are just a little noisy.

We'll see if this works as a permanent fix.
 
Still no kernel panics. Maximum temp has been 129f so it seems to be working. Weird thing though, the other day the airport card refused to turn on. Next day working fine again. Maybe a software issue?
 
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