mohammad462
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Re: repair raspberry pi 3 b

Mon Aug 27, 2018 10:59 pm

Yes
I found it.
I connected the negative USB pole to each of the polyfuse bases and the voltage was the same. :D

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Imperf3kt
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Re: repair raspberry pi 3 b

Tue Aug 28, 2018 2:32 am

drgeoff wrote:
Mon Aug 27, 2018 9:35 pm
@mohammad462

That is not the polyfuse. The polyfuse is on the underside of the board.
Specifically, if you face the board with the USB ports in your right hand, and the HDMI port facing the sky, you will find the polyfuse in the upper left section of the board, near the standoff hole.
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davidcoton
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Re: repair raspberry pi 3 b

Tue Aug 28, 2018 9:37 am

mohammad462 wrote:
Mon Aug 27, 2018 10:59 pm
Yes
I found it.
I connected the negative USB pole to each of the polyfuse bases and the voltage was the same. :D
Either I don't understand what you are saying, or you don't understand what you are doing.
I recommend that you stop before you do any more damage, though it sounds like your Pi is damaged already.
Possibly damage to the 5V output to USB, which could give the symptoms you describe.
Any repair is likely to need SMT soldering facilities, and a reasonable level of skill in SMT soldering.
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mahjongg
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Re: repair raspberry pi 3 b

Tue Aug 28, 2018 10:38 am

What you are pointing to is the over-voltage protection diode, it has 0V on the side that is connected to GND, and (+-) 5V on the side connected to the 5V line.
The polyfuse, identifiable by the fact that it is green, and has indentations in its connection points on both ends, has (about) 5V on both sides, (relative to GND) but if the voltage is not exactly the same (or if you measure some voltage across it) then the polyfuse has developed some resistance.

mohammad462
Posts: 14
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Location: IRAN

Re: repair raspberry pi 3 b

Tue Aug 28, 2018 3:09 pm

I found that polyfuse.
The voltage of both ends was 5 volts compared to GND.
This means healthy polyfuse.
Is there another suspicious part to be tested?
Did you look at photo 2? Why does it get usb to power?


Thank you for all the friends who help me.
I am not English and I have to use a Google translator. Because of this, my content may not be clear and clear.

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