mdog504
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Something small fell off my raspberry pi 4

Mon Feb 22, 2021 12:01 pm

I have no idea what it is, or if it is usable without it. Does anyone know what it is? Can I still use it safely?

(It is about 2mm by 1mm)


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drgeoff
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Re: Something small fell off my raspberry pi 4

Mon Feb 22, 2021 2:32 pm

From the information you have made available, no-one can determine whether or not your RPi4B will operate without that part. However you can be assured that you will be in no personal danger if you try to use your RPi4B in its current state.

Are you sure you are not guilty of a terminological inexactitude by writing that it "fell off".
Quis custodiet ipsos custodes?

mdog504
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Re: Something small fell off my raspberry pi 4

Mon Feb 22, 2021 2:43 pm

drgeoff wrote:
Mon Feb 22, 2021 2:32 pm
From the information you have made available, no-one can determine whether or not your RPi4B will operate without that part. However, you can be assured that you will be in no personal danger if you try to use your RPi4B in its current state.

Are you sure you are not guilty of a terminological inexactitude by writing that it "fell off"
Thanks for the help!

All I did was put a case on then I found it on my desk. It could have been me.
(it has also been operating as a server, which could have damaged it)

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davidcoton
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Re: Something small fell off my raspberry pi 4

Mon Feb 22, 2021 2:43 pm

Can you post a photo showing where on the board it fell from? If you can't see the gap, then good hi-res photos of both sides of the board.

Also, exactly which Pi4 (memory size and board revision)? Normally you find out with

Code: Select all

cat /proc/cpuinfo
but that doesn't help if the Pi doesn't work.

The full schematic is not published, so we may need help from a Pi engineer to identify the part.
Location: 345th cell on the right of the 210th row of L2 cache

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mahjongg
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Re: Something small fell off my raspberry pi 4

Mon Feb 22, 2021 2:51 pm

It looks like a 1206 ferrite, or ceramic capacitor, but I'm puzzled by the black mass around it, is that plastic?
are you sure it came off the PI?

mdog504
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Re: Something small fell off my raspberry pi 4

Mon Feb 22, 2021 3:09 pm

mahjongg wrote:
Mon Feb 22, 2021 2:51 pm
It looks like a 1206 ferrite, or ceramic capacitor, but I'm puzzled by the black mass around it, is that plastic?
are you sure it came off the PI?
the black stuff Is just mess on the side since its zoomed in so much

I don't use anything else with an exposed board, so it could only have come off the pi.

mdog504
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Re: Something small fell off my raspberry pi 4

Mon Feb 22, 2021 3:44 pm

davidcoton wrote:
Mon Feb 22, 2021 2:43 pm
Can you post a photo showing where on the board it fell from? If you can't see the gap, then good hi-res photos of both sides of the board.

Also, exactly which Pi4 (memory size and board revision)? .
It is has 4gb ram. The board revision is ‘c03111’

Images of pi:
https://ibb.co/n0Hw2NY
https://ibb.co/71CtTTj

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davidcoton
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Re: Something small fell off my raspberry pi 4

Mon Feb 22, 2021 4:21 pm

Looking at the underside, near TP34, there could be a part missing at the end of the lower track from TP34. TP34 is part of the power supply and is shown on the reduced schematic, but I can't tell which part it should be. If it is missing, and if the bit you have fits ... at your own risk, of course.

A side-on close-up photo of that site and the part you found might help -- or not.


EDIT: see gordon77's post below. I should have gone to a decent optician.
Last edited by davidcoton on Mon Feb 22, 2021 4:33 pm, edited 1 time in total.
Location: 345th cell on the right of the 210th row of L2 cache

gordon77
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Re: Something small fell off my raspberry pi 4

Mon Feb 22, 2021 4:29 pm

Here... something to do with the power supply?

I can't be certain but both lands maybe OK for resoldering..
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mdog504
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Re: Something small fell off my raspberry pi 4

Mon Feb 22, 2021 7:25 pm

gordon77 wrote: I can't be certain but both lands maybe OK for resoldering..
Will it be ok without it? I don’t know how to solder.

gordon77
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Re: Something small fell off my raspberry pi 4

Mon Feb 22, 2021 7:47 pm

mdog504 wrote:
Mon Feb 22, 2021 7:25 pm
gordon77 wrote: I can't be certain but both lands maybe OK for resoldering..
Will it be ok without it? I don’t know how to solder.
I don't know without knowing what it does. If you have powered it and all ok then I wouldn't worry about it.

gordon77
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Re: Something small fell off my raspberry pi 4

Mon Feb 22, 2021 9:35 pm

Looking at the schematic, and pictures of the pi4, it maybe C1 on the incoming 5v supply. Probably a bit of smoothing ?.

It may work OK without it.

I can't guarantee any of this.
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mdog504
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Re: Something small fell off my raspberry pi 4

Tue Feb 23, 2021 7:46 am

gordon77 wrote: Looking at the schematic, and pictures of the pi4, it maybe C1 on the incoming 5v supply. Probably a bit of smoothing ?.

It may work OK without it.

I can't guarantee any of this.
gordon77 wrote:
I don't know without knowing what it does. If you have powered it and all ok then I wouldn't worry about it.
It does power on and it does work

gordon77
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Re: Something small fell off my raspberry pi 4

Tue Feb 23, 2021 10:02 am

That's good. Maybe someone from RPF could confirm it is C1.

LTolledo
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Re: Something small fell off my raspberry pi 4

Tue Feb 23, 2021 10:10 am

if its indeed C1 and the same thing happened to my RPi4B...
I'd solder in a regular 10uF MLCC....

it wont look good at the bottom board.... but.... its the bottom board anyway...


edit some typo.... sorry..
Last edited by LTolledo on Tue Feb 23, 2021 10:12 am, edited 1 time in total.
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Come to me with 'problems' and I'll help you find solutions"

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gordon77
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Re: Something small fell off my raspberry pi 4

Tue Feb 23, 2021 10:11 am

LTolledo wrote:
Tue Feb 23, 2021 10:10 am
it its indeed C1 and the same thing happened to my RPi4B...
I'd solder in a regular 10uF MLCC....

it wont look good at the bottom board.... but.... its the bottom board anyway...
Thanks :D

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davidcoton
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Re: Something small fell off my raspberry pi 4

Tue Feb 23, 2021 11:24 am

mdog504 wrote:
Mon Feb 22, 2021 7:25 pm
I don’t know how to solder.
Two options:
  • Time to learn (though this repair is NOT a beginner task!) :shock: :?
  • Phone a friend 8-)
Location: 345th cell on the right of the 210th row of L2 cache

bjtheone
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Re: Something small fell off my raspberry pi 4

Tue Feb 23, 2021 1:01 pm

davidcoton wrote:
Tue Feb 23, 2021 11:24 am
mdog504 wrote:
Mon Feb 22, 2021 7:25 pm
I don’t know how to solder.
Two options:
  • Time to learn (though this repair is NOT a beginner task!) :shock: :?
  • Phone a friend 8-)
I would not suggest attempting to learn to solder via a fairly small chip package... :-) Learning how to solder is a great skill to acquire if you are going to muck about with electronics, but tiny 2 "lead" packages are a fair step up. 1210 or even 1206 are not too bad, but the smaller ones are tough to get tacked down without the surface tension of the solder ball shifting them.

If it is a decoupling cap, and the Pi boots and runs fine without it, I would not worry about it. Shorting out the 5V rail to ground with a solder blob will produce suboptimal results.

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Burngate
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Re: Something small fell off my raspberry pi 4

Tue Feb 23, 2021 6:35 pm

Also of note: C1 decouples the feed to the LDO that feeds the analogue audio circuitry; if you don't use the 3.5mm trrs socket, you won't gain by fixing it!

Also, shorting out C1 with a solder blob will drive 2.5W through R2, resulting in a sparkler.

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