Chosen Solution
I probably need a top specialist for the following problems What happened While I was writing an email, the fan started up to maximum speed, the system reacts with a delay. (Process kernel_task> 300%) What didn’t help SMC, PRAM, NVRAM reset What does Apple Diagnostics mean Last Run: 14/02/2021, 11:19 am Version: 1.1.38v4 Reference Code (s): PFM006 Apple Hotline recommended a visit to the Apple Service Provider - when I arrived, my iMac was analyzed, with the result that no errors were detected - the iMac behaved completely normally, which I was able to confirm later at home. I run an Apple diagnosis again - result = no error see query in the terminal: sudo powermetrics –samplers smc **** SMC sensors **** CPU Thermal level: 0 GPU Thermal level: 0 IO Thermal level: 0 Fan: 1202 rpm CPU the temperature: 49.02 C GPU the temperature: 40.00 C CPU limit: 0.00 GPU Plimit (Int): 0.00 GPU2 Plimit (Ext1): 0.00 Two days later, 1 second after switching on, the fan immediately goes to full speed, the system reacts again with a delay. The delay can be explained because in this state the CPU + GPU are clocked down (Plimit) see query in the terminal: sudo powermetrics –samplers smc **** SMC sensors **** CPU Thermal level: 255 GPU Thermal level: 255 IO Thermal level: 100 Fan: 3592 rpm CPU the temperature: 36.22 C GPU the temperature: 36.00 C CPU limit: 33.00 GPU Plimit (Int): 3 p.m. GPU2 Plimit (Ext1): 19.00 And this has been going on for a few weeks, a few days it’s going well, a few days it’s going bad. The SMC values that can be read out using the HWSensors tool are also interesting: some of these SMC values, which supposedly have something to do with the power supply, show this state: Tp2F () - 35, 35 Tp2H () - 128, 128 ——————> (what does that mean, value not available?) Tp2h () - 31.9375, 31.9375 …. if it goes well, then there are these values: Tp2F () - 32.6328, 32.6328 Tp2H () - 32.5, 32.5 Tp2h () - 32.5, 32.5 My question now is, what is going on with my iMac, what is broken, the logic board or the power supply - has anyone experienced this condition before? I would be happy to hear from you. Update (10/24/2021) To be honest, I don’t even want to know what I repaired with my stroke :-) When Apple finally launches the new 30-inch (or larger) iMac, the 27-inch will be sold immediately - although the iMac has currently been in use every day for months and without any problems.
The iMac has been running for 10 months after the fans were last turned on for no apparent reason. Last Sunday it was that time again, sometime in the afternoon it got really loud again in the office without anyone having worked on the imac, the fans were running at full speed again, only cold air came out of the outlet. Ok, I thought, packed the imac and made an appointment with Apple at the authorized Apple service provider, as I was 10 months ago. Thank goodness the imac showed the problem on site this time. The imac was checked and the next day the technician checked it more intensively. It was determined that the power supply has a problem, it has been replaced. And now I hope that that was it and that the (old) imac will stay with me a little longer.
Clearly you shifted something that fixed things! This could be anything from a bad sensor, cold-solder joint or data cable between the logic board and one of the sensors. I would install a good thermal monitoring app to help keep an eye on things. I find this app being one of the best TG Pro maybe it will get you what you need to find the failing connection/sensor.
