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A1398 820-00426-A Fans spinning max and very hot heatsink

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    A1398 820-00426-A Fans spinning max and very hot heatsink

    This MBP 15" Retina (2015) is running normal. The only problem is that the fans are often spinning maximum without any hard work for the cpu.

    I've already invested a lot in troubleshooting and can't get any further. I don't find any voltage errors or errors in the data lines. So far I haven't found any defective resistors or capacitors.

    I have already changed the following parts on the board: U7090 (LT3470AED), C7099, C7094, U7100 (ISL6259AHRTZ).
    I renewed the thermal paste and cleaned the board in the ultrasonic cleaner.

    I have no experience with this board yet. The removed board without battery consumes about 1.2A on the laboratory power supply. When switching on it goes up 1.7A - 2.1A then down to 1.9A and stays at 1.2A. When the temperature rises, the ampere consumption also rises - up to 1.3A or a bit higher. Are these normal values for this board?

    I read here in the forum that this board needs a good battery to boot. So i connected a good battery in addition to the laboratory power supply, the behavior and power consumption did not change.

    Can someone give me a tip on how I can continue.

    #2
    Re: A1398 820-00426-A Fans spinning max and very hot heatsink

    Hello,
    Maybe i found a fault on PPVCCIO_S0_CPU. I measure a resistance of 8 Ohm to ground. When i measure it on donor boards (without CPU on it) i get a value of 4.8MOhm. I only have donor boards to compare.

    I desoldered and checked the components connected to ground on this rail. This components are C7279, C1079, C1800 and C1801. I still measure 8 Ohms to ground.

    Measureing the resistors on this rail not connected to ground, gives me (i think) plausible values ...
    R7279 and R7280 = 55 Ohm
    R0531 = 2,47 kOhm
    R0601 = 61,5 Ohm
    R0800 = 75,4 Ohm
    R0802 = 55,5 Ohm
    This values i get more or less also at the donor boards.

    Can tell someone what's the normal resistance on this rail with CPU on it. Are the 8 Ohm normal? Or do i have maybe an damaged CPU?

    Maybe it is interesting how i came to PPVCCIO_S0_CPU as a fault:
    I re soldered the U7200 and did a misstake making a solderbridge between R7280(Pin2) and R7279(Pin2). Then i gave Power to the board and the Ampere usage looked like normal, using something about 650mA (instead of 1,3A before). I think 650mA is also a normal value for this board, or not? In the first moment i thougt i fixed the problem with this board. But then i saw the solderbridge :-(

    It would be very nice, if someone could help me a bit in this case to come further.

    Thank's a lot
    Micha

    Comment


      #3
      Re: A1398 820-00426-A Fans spinning max and very hot heatsink

      Low resistance to ground on CPU power rails is always expected, resistance is internal to the CPU. CPU VCCIO on these can be somewhere around 10 ohms (or a bit lower) to 20 ohms to ground (board dead cold and all power drained from it).
      Bridging R7280 and R7279 would prevent CPU from setting the correct CPU VCore voltage (well not actual VCore but what the board sends to the CPU anyway) and it won't POST.

      On a 3787 it does 20mA→1.1A→1.6A→2.0A→1.3A→1.1A. 00426 has a completely different GPU so power consumption will be a bit different.

      Running HWSensors under macOS will show what the reported temperatures are, monitoring temps, fan speed and CPU load to see if they are correlated.
      OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

      Comment


        #4
        Re: A1398 820-00426-A Fans spinning max and very hot heatsink

        Hello Piernov,
        Thanks for your reply. So the ampere usage of my 00426 with 1.2 to 1.3 A at the end could be normal? The next time I switch it on, I log the values more precisely than I have done yet. But it looks plausible, does it?

        I uploaded a HWSensors Screenshot that i created a view weeks ago (sorry it's German - i can create a new one in english if neccessary).

        There is a value with permanent 129°C named "Grafikkarte 2" (Graphiccard 2). What does the 129°C mean? Is this sensor not present on my board? Or is ist present and faulty? Cold this have to do with my problem?

        How can i go further with this informations? i already checked some data-lines without finding any fault.

        Here is the sensorlist i found at LogiWiki.

        Dumping MacBookPro11,5 from MacBookPro11_5
        Name: MacBook Pro (15 inch, Retina, Mid 2015)
        Memory: 2 slots with 16384 MB total
        Defaults: TCXC, temperature: TCXC
        Key IC0C low 0 high 0 CPU High (CPU, I/O)
        Key ID0R low 0 high 0 DC In
        Key IHDC low 0 high 0 SSD
        Key IPBR low 0 high 0 Charger (BMON)
        Key IC0R low 0 high 0 CPU
        Key IO3R low 0 high 0 Other 3.3V
        Key IO5R low 0 high 0 Other 5V
        Key IG0R low 0 high 0 Intel GPU
        Key IG0C low 0 high 0 Radeon GPU Core
        Key IG2C low 0 high 0 Radeon GPU VDDCI
        Key IM0C low 0 high 0 Memory
        Key IC1C low 0 high 0 Platform Controller Hub Core
        Key IBLC low 0 high 0 LCD Backlight
        Key IHSC low 0 high 0 Thunderbolt
        Key ITPC low 0 high 0 Trackpad Actuator
        Key TC0P low 0 high 0 CPU Proximity
        Key TP0P low 0 high 0 Platform Controller Hub
        Key TM0P low 0 high 0 Memory Proximity
        Key Ta0P low 0 high 0 Air Flow Proximity
        Key Th2H low 0 high 0 Left Fin Stack
        Key Th1H low 0 high 0 Right Fin Stack
        Key TG0P low 0 high 0 Radeon GPU Proximity
        Key TG0D low 0 high 0 Radeon GPU
        Key TW0P low 0 high 0 Airport Proximity
        Key Ts0P low 0 high 0 Palm Rest
        Key Ts1P low 0 high 0 Palm Rest Actuator
        Key TB1T low 0 high 0 Battery Sensor 1
        Key TB2T low 0 high 0 Battery Sensor 2
        Key TH0A low 0 high 0 SSD A
        Key TH0B low 0 high 0 SSD B
        Key TC1C low 0 high 0 CPU Core 1
        Key TC2C low 0 high 0 CPU Core 2
        Key TC3C low 0 high 0 CPU Core 3
        Key TC4C low 0 high 0 CPU Core 4
        Key TCXC low 0 high 0 CPU PECI Die
        Key TCGC low 0 high 0 Intel GPU
        Key TPCD low 0 high 0 Platform Controller Hub PECI
        Key TCSA low 0 high 0 CPU System Agent Core
        Key VC0C low 0 high 0 CPU VCore
        Key VD0R low 0 high 0 DC In
        Key VP0R low 0 high 0 Pbus
        Key VG0C low 0 high 0 Radeon GPU Core
        Key VG1C low 0 high 0 Radeon GPU FB
        Key ALSL low 0 high 0 Ambient Light
        Key F0Ac low 2160 high 6156 Leftside
        Key F1Ac low 2000 high 5700 Rightside
        Key PCPC low 0 high 0 CPU Package Core
        Key PCPG low 0 high 0 CPU Package GPU
        Key PCPT low 0 high 0 CPU Package Total
        Key PSTR low 0 high 0 System Total
        Key PDTR low 0 high 0 DC In
        Attached Files

        Comment


          #5
          Re: A1398 820-00426-A Fans spinning max and very hot heatsink

          Not sure what it's saying since it's in German, but I don't see the palm rest sensor in the touchpad. Make sure you are using the latest version (as far as I know this one is the newest: https://bitbucket.org/RehabMan/os-x-...-2018-0915.zip )
          Also try running Apple Diagnostics.
          Does fan spin at full speed right when turning on the machine or does it ramp up to full speed?
          OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

          Comment


            #6
            Re: A1398 820-00426-A Fans spinning max and very hot heatsink

            Hello piernov,

            You are right, i also see no palm rest sensor shown in HWMonitor. I installed the version you gave me in english. See also the Screenshots in the attachments. Should i find this sensor in the schematics of the 820-00426? I can't find there a Ts0P or Ts1P. If it is on the trackpad, is it connected over J4801 to the logicboard (ScreenShot of J4801 in the attachments)? Can you explane me how to find and measure this sensor?

            The Apple Diagnose didn't find any issue (Reference Code: ADP000).

            While booting up to the login the fans are running more or less normal with slow to medium speed. The first time the fans get full speed is after the login, while starting the startupprograms. There they run more than 6 Minutes nonstop in full speed before they go down to normal. After that they go back to highspeed with every little job.

            It would be nice if you could give me more hints to come further with this machine. I own this MB since 2015 and bought it new. But sometimes i'm short befor throwing it out of the window :-(

            Thanks for your time
            Micha
            Attached Files

            Comment


              #7
              Re: A1398 820-00426-A Fans spinning max and very hot heatsink

              Ok I thought it was getting stuck at high speed since it was what the previous screenshot was showing.

              On these newer screenshots it looks more normal, even though the fan response seems more aggressive than what I'm used to, but it's not getting stuck at 6000RPM at least. It follows the change in temperature, and the change in temperature itself follows the change in power consumption, so here everything is normal.

              What is less normal is if the power consumption increases that much when the machine isn't under full load. It can also be seen that the "CPU Package Graphics" reports 22W of power consumption on the 1st screenshot, which means the iGPU is under stress.
              On the 2nd and 3rd screenshots the CPU is periodically spiking up in power consumption, and the temps are following too.
              On the 3rd screenshot, at the end of it the fan starts ramping up because there was suddenly a huge increase in power consumption, which also caused a sudden high temperature on the CPU. The CPU reaches 100°C so the fan will ramp up to 6000RPM. Additionally when there's the spike in temperature at the end of the graph, the slope look very steep. I can't make out the scale very well but it looks like it takes 20°C very quickly then another 20°C in a bit more time.

              Unfortunately on these graphs we cannot see the CPU/iGPU load and frequency (Intel Power Gadget could give more details), but I'm pretty sure the CPU is at or near 100% usage at this point.

              I think for the most part the issue is on the software side, something is loading up the CPU a lot at random times, and also putting a bit of load periodically. This will of course make the CPU heat up randomly.
              And I'm not sure about it since I don't have this exact machine to compare, but there may be a bit of heat transfer issue since the spike in temperature are very quick.

              So first I'd start from a clean fresh macOS installation, without adding apps that can run background tasks.
              I'd replace the thermal paste with something high quality (not the random stuff that comes with CPU from Aliexpress, you may as well be using toothpaste…), make sure the heatsink is attached properly and making good contact with the CPU, make sure the laptop is used in a way that it can dissipate heat efficiently (on a desk with proper room around it and no heater blowing on it or stuff like that), remove all dust from the heatsink fins, and if it's still not working as intended, try another heatsink.
              OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

              Comment


                #8
                Re: A1398 820-00426-A Fans spinning max and very hot heatsink

                Hello piernov,
                thank you very much for your detailed analyse of the diagrams. Here is what i did with the machine the last days:

                I always use the thermal paste MX-4 from Arctic - i hope/think it is a good one. i renewed it two or three times in the last weeks - so here i had nothing to do.

                I did a complete new installation with Big Sur Beta (V11) like you told me - without any apps who are running background tasks. The machine runs now much more better than before. I think your guess that the problem is mainly software based was totaly right. After hours of testing and analysing with HWMonitor, activity indicator and Intel Power Gadget (thanks for this tip) i installed more and more the software i use normaly. The machine runs now almost normal. I will now using it again in my daily work and will continue to observe it.

                But something is still not 100% ok. I followd all of your tips - but sometimes the temperatures are going straight up to 90-100°C and the fans to 5000-6000-RPM. In the next step i will change the heatsink. But i'm not sure if this could be the problem. I watched the heat dissipation with my thermal camera and it looks like normal how the heat goes from the cpu to the heatsink fins where the fans are blowing the heat away. Even if the CPU goes up to 90-100°C, the cooling-system brings it fast down. Also the aluminium-case goes very hot - so i think this is a good sign that the heat will be transported away from the cpu.

                How ever - i think the case can be closed here. I thank you so much for your help and time. I will return it here in the forum whenever I can.

                Comment

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