Fan not working, CPU overheating, throttling, turning down unexpectedly. There are knocking, high-pitch buzz or similar sounds from fan, faster with temperature rise (this is actually the PWM sound that is trying to spin fan faster, but it can't spin at all).
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The problem is not in fan itself, fan is OK. The power to fan is delivered through a small resistor at the mainboard (actually, under the microscope, it looks more like coil, not resistor). Overtime it degrades and in my case was 40 Ohm, which is way too much voltage drop to start a 0.5A fan.
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The problem is not in fan itself, fan is OK. The power to fan is delivered through a small resistor (UPD: as ***[link|https://ru.ifixit.com/User/278657/elektrosha|elektrosha|new_window=true] ***discovered, it is a permanently failed resettable fuse) at the mainboard. Overtime it degrades and in my case was 40 Ohm, which is way too much voltage drop to start a 0.5A fan.
So the steps are (on your risk of course):
# You disassemble the laptop (powered off, unplugged). There are 2 types of screws, long and short, mark by any sort of scotch tape the places where were the short ones. Some small latches, open the screen and keyboard kicks off.
# Disconnect the battery from the motherboard. There is a obvious connector from battery to MB in the center.
# Locate the %#*@ 0603-size resistor 1cm to the right to the fan connector, under the metal sheet. I completely removed it, but it is actually not needed (as it is 40ohm or so, and we are planning to solder 3-4ohm, you can just solder new one over the old one). There are no any other parts in there, so it's really hard to damage anything. The resistor is glued & soldered, so it would require some scraping with your soldering tip or hot air to actually desolder it, pain in the ass. Better just solder new one over the old one. I've done this under the microscope, but good magnifying glass would help.
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[image|3026360]
#
# I tried 20ohm (half the "old" value), the fan started and worked, but at very small speeds, if I placed 100% load to all the cores, it overheated. So my choice is 3ohm about. I guess anything between 2 to 4 ohm would be ok.
# In fact, you can even use just solder blob to short-circuit it (try not to solder it to metal sheath nearby, it's grounded), but if fan fails short-circuit, it would drain enormous amount of current and would fire the motherboard internal PSU somewhere. But, as a temporary solution if you don't have any 0603 resistors on hand, it would work.
Fan not working, CPU overheating, throttling, turning down unexpectedly. There are knocking, high-pitch buzz or similar sounds from fan, faster with temperature rise (this is actually the PWM sound that is trying to spin fan faster, but it can't spin at all).
The problem is not in fan itself, fan is OK. The power to fan is delivered through a small resistor at the mainboard (actually, under the microscope, it looks more like coil, not resistor). Overtime it degrades and in my case was 40 Ohm, which is way too much voltage drop to start a 0.5A fan.
So the steps are (on your risk of course):
# You disassemble the laptop (powered off, unplugged). There are 2 types of screws, long and short, mark by any sort of scotch tape the places where were the short ones. Some small latches, open the screen and keyboard kicks off.
# Disconnect the battery from the motherboard. There is a obvious connector from battery to MB in the center.
# Locate the %#*@ 0603-size resistor 1cm to the right to the fan connector, under the metal sheet. I completely removed it, but it is actually not needed (as it is 40ohm or so, and we are planning to solder 3-4ohm, you can just solder new one over the old one). There are no any other parts in there, so it's really hard to damage anything. The resistor is glued & soldered, so it would require some scraping with your soldering tip or hot air to actually desolder it, pain in the ass. Better just solder new one over the old one. I've done this under the microscope, but good magnifying glass would help.
-
#
[image|3026360]
#
# I tried 20ohm (half the "old" value), the fan started and worked, but at very small speeds, if I placed 100% load to all the cores, it overheated. So my choice is 3ohm about. I guess anything between 2 to 4 ohm would be ok.
-
# In fact, you can even use just solder blob to short-circuit it, but if fan fails to short-circuit, it would drain enormous amount of current and would fire the motherboard internal PSU somewhere. But, as a temporary solution if you don't have any 0603 resistors on hand, it would work.
+
# In fact, you can even use just solder blob to short-circuit it (try not to solder it to metal sheath nearby, it's grounded), but if fan fails short-circuit, it would drain enormous amount of current and would fire the motherboard internal PSU somewhere. But, as a temporary solution if you don't have any 0603 resistors on hand, it would work.
Update on what Darko said above:
Fan not working, CPU overheating, throttling, turning down unexpectedly. There are knocking, high-pitch buzz or similar sounds from fan, faster with temperature rise (this is actually the PWM sound that is trying to spin fan faster, but it can't spin at all).
The problem is not in fan itself, fan is OK. The power to fan is delivered through a small resistor at the mainboard (actually, under the microscope, it looks more like coil, not resistor). Overtime it degrades and in my case was 40 Ohm, which is way too much voltage drop to start a 0.5A fan.
So the steps are (on your risk of course):
# You disassemble the laptop (powered off, unplugged). There are 2 types of screws, long and short, mark by any sort of scotch tape the places where were the short ones. Some small latches, open the screen and keyboard kicks off.
# Disconnect the battery from the motherboard. There is a obvious connector from battery to MB in the center.
# Locate the %#*@ 0603-size resistor 1cm to the right to the fan connector, under the metal sheet. I completely removed it, but it is actually not needed (as it is 40ohm or so, and we are planning to solder 3-4ohm, you can just solder new one over the old one). There are no any other parts in there, so it's really hard to damage anything. The resistor is glued & soldered, so it would require some scraping with your soldering tip or hot air to actually desolder it, pain in the ass. Better just solder new one over the old one. I've done this under the microscope, but good magnifying glass would help.
#
[image|3026360]
#
# I tried 20ohm (half the "old" value), the fan started and worked, but at very small speeds, if I placed 100% load to all the cores, it overheated. So my choice is 3ohm about. I guess anything between 2 to 4 ohm would be ok.
# In fact, you can even use just solder blob to short-circuit it, but if fan fails to short-circuit, it would drain enormous amount of current and would fire the motherboard internal PSU somewhere. But, as a temporary solution if you don't have any 0603 resistors on hand, it would work.