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.
55:55:44:44:4C
52:4C:52:42:41

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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: 17
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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.

mohammad462
Posts: 17
Joined: Fri May 18, 2018 3:19 pm
Location: IRAN

Re: repair raspberry pi 3 b

Thu Sep 05, 2019 8:11 pm

Anyone have any tips?
My device is fully bootable and the operating system goes up only the network and the USB do not have power. The red light is on but the green light is off.
The yellow mark is on the top corner of the image, but I replaced the power and cable several times with new ones.

mohammad462
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Location: IRAN

Re: repair raspberry pi 3 b

Sun Sep 08, 2019 9:13 pm

Is the SMSC LAN9514 chip likely to be burnt?

LTolledo
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Re: repair raspberry pi 3 b

Mon Sep 09, 2019 10:48 am

Save yourself trouble, frustration and time ....get yourself a new one (RPi3B+ or RPi4B-1G)...

and put your faulty RPi3B in a picture frame.... as a reminder of something that went wrong with your setup...

....or is it really because the RPi boards are very expensive and/or hard to get in your area and that repair "looks easy and cheap"....
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"

Some people be like:
"Help me! Am drowning! But dont you dare touch me nor come near me!"

mohammad462
Posts: 17
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Location: IRAN

Re: repair raspberry pi 3 b

Tue Sep 10, 2019 3:33 pm

LTolledo wrote:
Mon Sep 09, 2019 10:48 am
Save yourself trouble, frustration and time ....get yourself a new one (RPi3B+ or RPi4B-1G)...

and put your faulty RPi3B in a picture frame.... as a reminder of something that went wrong with your setup...

....or is it really because the RPi boards are very expensive and/or hard to get in your area and that repair "looks easy and cheap"....
I need this device.
Buying a new one is expensive.
Help me fix it.

fruitoftheloom
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Re: repair raspberry pi 3 b

Tue Sep 10, 2019 4:32 pm

mohammad462 wrote:
Tue Sep 10, 2019 3:33 pm
LTolledo wrote:
Mon Sep 09, 2019 10:48 am
Save yourself trouble, frustration and time ....get yourself a new one (RPi3B+ or RPi4B-1G)...

and put your faulty RPi3B in a picture frame.... as a reminder of something that went wrong with your setup...

....or is it really because the RPi boards are very expensive and/or hard to get in your area and that repair "looks easy and cheap"....
I need this device.
Buying a new one is expensive.
Help me fix it.

It is over a year you have been attempting to resolve your issues, is it not best to admit defeat ??
Retired disgracefully.....

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