Random power failure even after several attempts to rectify.

The 2011 Mac Mini has two versions. Which do you have?

Also did you run TG Pro? It should have given you some temp info.

Apple Mac mini "Core i5" 2.5 (Mid-2011)

It does not stay up long enough to run anything.

I could occasionally run SMCFancontrol, and the internal temp wold run 90-95c. That was before I replaced the fan.

95C (203F) is quite hot just booting up! But, without any idea what is getting hot I can't offer any insight here. You need to find a way to run TG Pro as it will disclose which sensor is running hot. SMCFanControl is not very good in diagnostics.

The 2011 Mac Mini has two versions. Which do you have?

Also did you run TG Pro? It should have given you some temp info.

The computer won't stay on long enough to boot. It will go into recovery mode, but that's after several restarts. Afterwards, it won't boot normally at restart, nor will it boot into verbose mode. I have the 5.2 version mac mini 2011, 2.5ghz with the Radeon graphics. I was speaking with a few other mac parts sellers and they are stating it sounds like the logic board is the component that is going bad. It's not looking good in terms of finding a logic board replacement, so I may have to just cut my losses, buy an external drive case for the HD's and just sell the mac mini for parts. Even if TG pro could run and could tell me that something was overheating, who's going to fix it? A lot of places only repair macbook logic boards, not mini's. Also, baking doesn't last very long from what I've researched from others who have had this issue. And as I've stated before, the logic board is hard to find. It's a shame because I really liked this system, but looks like it won't be sticking around.

@msalejandro1201 - It does appear the dedicated GPU models tend to have more of a problem. Have you tried replacing the heat sink? I encountered a few which had bad heat pipes. To see if the heat pipe issue the issue try cooling your system down (don't freeze it!) Wrap the system up tight in a plastic bag and put in the refrigerator for a few hours see if that improves things.

I didn’t bother replacing the heat sink. too much work. need to buy more thermal paste and just spend more and more time on it. the heat pipes have been working fine for the past 6yrs, so i don’t think it’s the issue. i need more definitive trouble shooting. i don’t want to keep spending night after night coming home from work taking it apart and putting it back together over and over. it’s more frustration than anything else. i took out the ssd and am cloning the drive now. apparently now the ssd is popping up as failing soon according to my macbook air. so i put it in an external case and just copying all my stuff off. 6 years has served its purpose. i think someone will buy the machcine for parts.

The heat pipe is filled with fluid so it may appear good. Sometimes you'll see some staining or white powder. The only way to tell is to use a good digital scale and compare it to a known good one. Apple uses a combo heat sink for both chips.

As for testing if thats it I gave you the test getting the system cool in the refrigerator.

Here's the IFIXIT guide: Mac Mini Mid 2011 Heat Sink Replacement

The Radeon HD 6630M GPU chip was a common failure in this series. The cooling system was just not able to service both the CPU & GPU with antiquate cooling

The Radeon HD 6630M is whats called a flip chip and it's the solder joints within the chip that are failing.

The BD82HM65 PCH issues what with the other version of the system which had only the Intel HD Graphics 3000 services.

Thanks @danj for the reply, I will attempt a reflow on the PCH of my machine, please wish me luck. I may document my progress in another thread. If anyone has any tips on temperature and time, that would be great..

Your system uses a custom combo chip. The PCH is part of the GPU chip. Reflow won't really fix the issue here. While you might get it to work for a while it won't be able to handle much stress afterwards. Blender is to heavy a work load in this weaken state.

Thanks for your messages, @danj. It's unfortunate and frustrating that these machines were never addressed by Apple properly, even with a well documented problem and many machines left in the dark.