hoang
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Raspberry pi 4 get really hot

Thu Jan 16, 2020 2:57 pm

Hi!
My raspberry pi 4 is much hotter than my pi 3B+, even without any program are running, especially this capacitor (under the power LED) gets extremely hot that I can not touch it. Is that normal?
Thanks
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fruitoftheloom
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Re: Raspberry pi 4 get really hot

Thu Jan 16, 2020 4:10 pm

removed irrelevant response....................
Last edited by fruitoftheloom on Thu Jan 16, 2020 5:47 pm, edited 1 time in total.
Retired disgracefully.....
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Re: Raspberry pi 4 get really hot

Thu Jan 16, 2020 5:17 pm

fruitoftheloom wrote: This subject has been covered as recently this week, so to save you searching see:

https://www.raspberrypi.org/forums/view ... 3&t=262023
That thread
a) doesn't mention a single component getting exceptionally hot
b) doesn't help the OP troubleshoot the issue.

The capacitor is part of one of the power supply outputs. It's more likely that something has failed elsewhere on the board and is drawing excessive current. Are there any other components other than the main SoC that are also hot?
Rockets are loud.
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hoang
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Re: Raspberry pi 4 get really hot

Thu Jan 16, 2020 5:41 pm

Oh man what is that capacitor for? Can raspberry pi work without it? I think soder start melting and the capacitor is falling out.

emma1997
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Re: Raspberry pi 4 get really hot

Thu Jan 16, 2020 5:54 pm

I think there have recently been more than one report of that part mysteriously missing from the board. Now we may see the reason why. If ripple exceeds a certain value switcher output caps are known to overheat and even unsolder themselves. Generally due to improperly rated cap. I've personally seen this happen on designs I went too far cutting corners.

A high drain (illegal!) load on the 3.3v rail could generate enough ripple current to do this too. I make sure not to take more than few ma from there if that. Others I know of are running fans, so good luck with that. Or could just be coincidence or bad component.

hoang
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Re: Raspberry pi 4 get really hot

Thu Jan 16, 2020 5:58 pm

jdb wrote:
Thu Jan 16, 2020 5:17 pm
fruitoftheloom wrote: This subject has been covered as recently this week, so to save you searching see:

https://www.raspberrypi.org/forums/view ... 3&t=262023
That thread
a) doesn't mention a single component getting exceptionally hot
b) doesn't help the OP troubleshoot the issue.

The capacitor is part of one of the power supply outputs. It's more likely that something has failed elsewhere on the board and is drawing excessive current. Are there any other components other than the main SoC that are also hot?
I check with my hand, only the capacitor get really hot. The temperature decrease further away from the capacitor. My raspberry pi is still working. I'm so worry so I shut it down.

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mahjongg
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Re: Raspberry pi 4 get really hot

Thu Jan 16, 2020 6:20 pm

Not being able to touch "hot components" is normal, your body cannot endure temperatures above say 60 degrees Celsius, (protein solidifies at 63 degrees) so everything above that that has good thermal conductance (metal and ceramic) will be "too hot to touch", but parts can be much hotter than 60 degrees Celsius while being fine, 85 degrees is "normal".

Please try if the main chip (SoC) heats up without an sd-card, if it heats up there is something wrong.

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Re: Raspberry pi 4 get really hot

Thu Jan 16, 2020 6:24 pm

hoang wrote:
Thu Jan 16, 2020 5:41 pm
Oh man what is that capacitor for? Can raspberry pi work without it? I think soder start melting and the capacitor is falling out.
for (lead free) solder to melt it needs a few hundred degrees celcius (207 degrees), not being able to touch it isn't a good indicator, it should start smoking (flux residue) far before the solder really melts.

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rin67630
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Re: Raspberry pi 4 get really hot

Thu Jan 16, 2020 8:02 pm

hoang wrote:
Thu Jan 16, 2020 5:41 pm
Oh man what is that capacitor for? Can raspberry pi work without it? I think soder start melting and the capacitor is falling out.
A capacitor should not get hot unless it is defective or notoriously overloaded.

Here is a thermal image of a Raspberry Pi
https://twitter.com/ghalfacree/status/1 ... 98/photo/1
The capacitor is not hot.

You may have got a defective component.

hoang
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Re: Raspberry pi 4 get really hot

Fri Jan 17, 2020 3:14 am

mahjongg wrote:
Thu Jan 16, 2020 6:20 pm
Not being able to touch "hot components" is normal, your body cannot endure temperatures above say 60 degrees Celsius, (protein solidifies at 63 degrees) so everything above that that has good thermal conductance (metal and ceramic) will be "too hot to touch", but parts can be much hotter than 60 degrees Celsius while being fine, 85 degrees is "normal".

Please try if the main chip (SoC) heats up without an sd-card, if it heats up there is something wrong.
The main chip does not heat up without an SD-card.
I touch the capacitor lightly and one of its legs has broken :o . Do you know the value of this capacitor? I will replace a new one.
Image

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rin67630
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Re: Raspberry pi 4 get really hot

Fri Jan 17, 2020 6:10 am

hoang wrote:
Fri Jan 17, 2020 3:14 am
I touch the capacitor lightly and one of its legs has broken :o . Do you know the value of this capacitor? I will replace a new one.
According to the schematic it should be a 22μF 6,3v
But you ought to have asked for a warranty. Now it's probably too late...

By the way I measured the temperatures of a Pi4 idling with a pyrometer:
the processor runs a 37°C* like a sane human :)
the power chip close to your capacitor runs at 41°c.
The Pi4 draws 450mA at 5V at idle.

*the 37°C being metallic feels hotter than it is really.

user12345
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Re: Raspberry pi 4 get really hot

Fri Jan 17, 2020 11:02 am

hoang wrote:
Fri Jan 17, 2020 3:14 am
I touch the capacitor lightly and one of its legs has broken :o . Do you know the value of this capacitor? I will replace a new one.
Your warranty will lost if you solder on the Board, send it back.
Its possible that other broken parts makes heat up the capacitor...
Thats ones with high capacity over 1µF are known to be sensitive with longer soldering.
They short circuit(0 Ohm). If the PI is able to boot it sounds more like a different problem.

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Re: Raspberry pi 4 get really hot

Fri Jan 17, 2020 1:12 pm

Raspberry pi is not official selling in my area, so asking for a warranty is pretty complicated.
Now the capacitor has completely fallen off. But for some reason my pi still working just fine, even with lower temperature than yesterday. I think I will leave it that way.
I just wonder what is this capacitor for?

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Re: Raspberry pi 4 get really hot

Fri Jan 17, 2020 5:52 pm

Its one of the capacitors used in the quad regulator (PMIC), difficult to say which one.
RPI4_power.PNG
RPI4_power.PNG (99.93 KiB) Viewed 209 times
The inductor R1 is on the opposite corner of the square chip in the middle, and has R47 printed on it, its used for the 3V3 generation, so its not C4.

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Re: Raspberry pi 4 get really hot

Fri Jan 17, 2020 10:06 pm

The PMIC chip looks QFP with legs exposed so it should be possible to tell which leg it connects to witha continuity check. My guess would be it's across 0V and 5V for decoupling, of which there are a few, so probably why it's still working without it. Maybe not optimally. If it is to 0V/5V that's even easier to check.

I don't have a 4B to hand to check with or I'd do that.

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Re: Raspberry pi 4 get really hot

Sat Jan 18, 2020 11:02 am

I've not actually bought a 4B yet (I know, I know, I will, one of these days) so this is just going on the various pictures I've found.

But 5v goes in on pins 12 & 13, and pins 28 & 29. On that first pic in the first post, you can clealy see those pairs of pins joined together with paralleled caps, top and bottom of the chip. Also, the big inductor marked "R47" must be L4, connected to pins 14, 15 & 16
So we can work out the orientation of the chip. And the "hot" cap isn't any of C3, C5, C7 or C9.

My guess is it's C4, on the 3v3 rail
And it's still working because there are other caps on that rail, elsewhere

user12345
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Re: Raspberry pi 4 get really hot

Sat Jan 18, 2020 1:03 pm

hoang wrote:
Fri Jan 17, 2020 1:12 pm
Raspberry pi is not official selling in my area, so asking for a warranty is pretty complicated.
Now the capacitor has completely fallen off. But for some reason my pi still working just fine, even with lower temperature than yesterday. I think I will leave it that way.
I just wonder what is this capacitor for?
That i dont understand. If you buy a device from outside your country you still have warranty. The lowest warranty you get worldwide would be 1year.

Dont leave it that way, if you realy want keep the PI and dont want use warranty you have to replace it!
There are about 1.1V on it, in the (limited) schematics there are only 4 "big" capicators, the 3 around L4 are parallel.
So it can be only C8 47µ/6.3V 1V1_DDR, its a capicator for the stepdown. A stepdown produce voltage spikes without this and destroy what
is connected to it, means the Rasperry Memory. There are some capicators around the Memory chip(with working C8 its about 85µ total), cause it works temporary.

You can replace the capicator with the same type(voltage can be higher but not lower) if you unable to get it(rare size for 47µ) you can solder 2 or 3 22µ/6.3V stacked. https://www.reichelt.de/vielschicht-ker ... 07090.html
The size seems 0805 2mmx1.25mm

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Re: Raspberry pi 4 get really hot

Sat Jan 18, 2020 2:48 pm

It might just be the lighting, but it looks to me that the OP's Pi4 somehow got coated in smoke.
x8taYYc-min.jpg
x8taYYc-min.jpg (210.94 KiB) Viewed 62 times
So maybe the bad capacitor is a symptom of a bigger problem.
My doctor told me my brain is as useful as a Raspberry Pi. Is that a compliment?

hippy
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Re: Raspberry pi 4 get really hot

Sat Jan 18, 2020 11:32 pm

user12345 wrote:
Sat Jan 18, 2020 1:03 pm
hoang wrote:
Fri Jan 17, 2020 1:12 pm
Raspberry pi is not official selling in my area, so asking for a warranty is pretty complicated.
That i dont understand. If you buy a device from outside your country you still have warranty. The lowest warranty you get worldwide would be 1year.
Not necessarily. The only warranty one has for a Pi is with the seller of it and if they say they are not obliged to give any warranty ( and that may be the case ), simply say "no", or claim the damage was self-inflicted and not covered by warranty, there are not a lot of options left after that. Not any simple options anyway. Other than suck it up and buy a new one.

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