mohammad462
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repair raspberry pi 3 b

Fri May 18, 2018 3:25 pm

My device has a picture, but the blue dot is blue.
All four usb numbers do not work.
The red LED lights up, but the yellow does not light up.
My device model is Pi3B v1.2.

#This text is translated from Persian to English by Google Translator#

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mahjongg
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Re: repair raspberry pi 3 b

Fri May 18, 2018 5:33 pm

You have a problem booting the PI.

I have used google translate to translate the boot problem sticky, please click on below link and read the translated sticky.

شما مشکلی در بارگذاری PI دارید

من از ترجمه گوگل برای ترجمه مشکل بوت چسبناک استفاده کردم، لطفا روی پیوند زیر کلیک کنید و چسبنده ترجمه را بخوانید.

https://translate.google.nl/translate?s ... edit-text=

mohammad462
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Re: repair raspberry pi 3 b

Sat May 19, 2018 11:10 pm

thanks for your answer.
I do not understand what you mean.
The boot operation is fully executed and the operating system goes up.
Desktop is displayed.
But the USB ports do not work. Like the keyboard and mouse.
And still in the corner of the image, the yellow symbol blinks

fruitoftheloom
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Re: repair raspberry pi 3 b

Sun May 20, 2018 6:47 am

mohammad462 wrote:
Sat May 19, 2018 11:10 pm
thanks for your answer.
I do not understand what you mean.
The boot operation is fully executed and the operating system goes up.
Desktop is displayed.
But the USB ports do not work. Like the keyboard and mouse.
And still in the corner of the image, the yellow symbol blinks

Your power supply is not any good if you see this flashing:

https://www.raspberrypi.org/documentati ... g-icons.md
adieu

My other Computer is an Asus CS10 ChromeBit running Chrome Operating System.
HP Envy 4500 Wireless Printer supported by HPLIP software in Raspbian Buster.
Raspberry Pi Model 2B v1.1

mohammad462
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Re: repair raspberry pi 3 b

Sun May 20, 2018 9:39 am

I checked the voltage. 5.2 volt.
The adapter used also produces 3 amps of current.
I also checked with another power supply, still showing that yellow mark.
The mark is not important. The main thing is that the usb does not work

StuartF
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Re: repair raspberry pi 3 b

Sun May 20, 2018 2:29 pm

It could be that the LAN chip is faulty. Does it get hot?

Are you connecting USB devices directly into the pi or through a USB hub?

Does the yellow led come on if you connect the network cable?

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billybangleballs
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Re: repair raspberry pi 3 b

Sun May 20, 2018 2:43 pm

Good power supplies are often let down by cheap cables that are ridiculously thin and cannot pass the required current.
Grumpy old man.
Ex-G0KAP - I'd rather be doing it than talking about it.
"When found, make a note of." - Captain Cuttle

mohammad462
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Re: repair raspberry pi 3 b

Sun May 20, 2018 4:39 pm

StuartF wrote:
Sun May 20, 2018 2:29 pm
It could be that the LAN chip is faulty. Does it get hot?
lan and wireless not work.no not hot

Are you connecting USB devices directly into the pi or through a USB hub?
I connect the mouse and keyboard directly to the device directly.
When the power is connected to the device, the mouse light turns on and off for one second.
Does the yellow led come on if you connect the network cable?
No, the cable network lights are off

mohammad462
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Re: repair raspberry pi 3 b

Sun May 20, 2018 4:41 pm

billybangleballs wrote:
Sun May 20, 2018 2:43 pm
Good power supplies are often let down by cheap cables that are ridiculously thin and cannot pass the required current.
To solve this problem, I also used a power supply and another cable. But the problem was not resolved.

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mahjongg
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Re: repair raspberry pi 3 b

Sun May 20, 2018 6:30 pm

mohammad462 wrote:
Sun May 20, 2018 9:39 am
The mark is not important. The main thing is that the usb does not work
wrong :!:, if the lightening symbol burns, your PI, and thus also your USB devices do NOT receive the at least 4.75V they need to operate, as the lightening symbol tells you that the 5V, at least temporarily, dips below 4.65V.

You say you measured 5.2V, WHERE did you measure that, and under which conditions? And did you measure with an oscilloscope on the 5V signals on the PI to see if the 5V was steady, without dips in it below 4.75V?


That said, if both the USB, and the ethernet are not functioning, I would assume the LAN9515 is not working either, (as that chip is responsible for both USB and Ethernet) especially if you enter a live (that is a cable connected to an ethernet device) cable into the ethernet port, the ethernet activity LED's on that port should light up, if they don't I would suspect a dead LAN9515 chip.

That chip runs on 3V3, so its worth checking if your PI produces 3V3.

I tend to go with the idea you have either a broken LAN9515 CHIP, or 3V3 power supply. maybe an overload (short) in the 3V3 supply that draws the 5V line low, or a (halfway) burned out polyfuse.

p.s. I have never understood what you meant by:
but the blue dot is blue.
care to explain?

mohammad462
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Re: repair raspberry pi 3 b

Fri Jun 01, 2018 5:51 pm

Power supply output was measured with multi-meter.
A new power supply was tested.
Please say what you mean by the end of your speeches.
I have not noticed.

"""" That said, if both the USB, and the ethernet are not functioning, I would assume the LAN9515 is not working either, (as that chip is responsible for both USB and Ethernet) especially if you enter a live (that is a cable connected to an ethernet device) cable into the ethernet port, the ethernet activity LED's on that port should light up, if they don't I would suspect a dead LAN9515 chip.

That chip runs on 3V3, so its worth checking if your PI produces 3V3.

I tend to go with the idea you have either a broken LAN9515 CHIP, or 3V3 power supply. maybe an overload (short) in the 3V3 supply that draws the 5V line low, or a (halfway) burned out polyfuse.""""

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Re: repair raspberry pi 3 b

Fri Jun 01, 2018 8:23 pm

mohammad462 wrote:
Fri Jun 01, 2018 5:51 pm
That chip runs on 3V3, so its worth checking if your PI produces 3V3.
The SoC and SD Card both use 3V3 so if the Pi is booting it seems unlikely it is a 3V3 supply failure.

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Re: repair raspberry pi 3 b

Sun Jun 03, 2018 2:43 pm

Yes that's right.
What parts might be burned?
Please tell everyone about everything

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mahjongg
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Re: repair raspberry pi 3 b

Sun Jun 03, 2018 3:01 pm

The LAN9514 chip also uses 1V8, but its much harder to look for its absence, see LAN9514 datasheet:
https://www.google.nl/url?sa=t&rct=j&q= ... D1ohAO5Xrn

the yellow lightening symbol indicates your PI uses too much power, which means that the LAN9514 chip might be damaged somehow, and draws an excessive amount of current, especially if it gets unreasonably hot.

in my humble opinion your PI is defective, and you should try to return it to the seller, and ask your money back.

hippy
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Re: repair raspberry pi 3 b

Sun Jun 03, 2018 4:53 pm

mahjongg wrote:
Sun Jun 03, 2018 3:01 pm
The LAN9514 chip also uses 1V8, but its much harder to look for its absence, see LAN9514 datasheet:
https://www.google.nl/url?sa=t&rct=j&q= ... D1ohAO5Xrn
I don't believe that is correct; the LAN9514 only uses 3V3 according to its datasheet and that reference design.

The LAN9514 generates its own VDD18CORE 1V8 voltage, plus the VDD18USBPLL 1V8 voltage which goes to the VDD18ETHPLL 1V8 input. That's why there are no other generators of 1V8 shown on the reference design, only power filtering for those 1V8 signals.

So while the LAN9514 technically "uses 1V8" it doesn't use the Pi's generated 1V8 which is used elsewhere on the board. Absence of 1V8 elsewhere would not affect the LAN9514.

I believe that was the same for the earlier boards which used the LAN9512, and that was why there was an overheating issue after someone made the design error mistake of not realising VVD18CORE was an output from the LAN9512 and connected 1V8 from a voltage regulator to that. Forcing 1V8 into the LAN9512 1V8 output consequently caused the LAN9512 to overheat in some cases.

The older Pi-B boards used a 25MHz crystal for clocking the LAN9512. I have no idea what the Pi-B+ boards use because the LAN9514 and the rest of the related circuitry is not shown in the published circuit diagram. If the crystal isn't oscillating, or whatever provides the clocking is not running, that could explain why the LAN9514 appears to be dead, is unresponsive.

mohammad462
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Re: repair raspberry pi 3 b

Sun Jun 03, 2018 7:46 pm

There is one thing that is very strange for me.
When you connect the power supply, both the usb and the lan will be energized for a second.

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Re: repair raspberry pi 3 b

Wed Jun 06, 2018 4:41 pm

@Hippy,

yes, the term "uses 1V8" is somewhat confusing, as the LAN9514 contains a LDO and it makes its own 1V8.
That is exactly the reason of the overheating problem that occurred with the very first versions of the very first model of the PI, where the local 1V8 LDO's 1.8V output was abusively connected with the 1V8 output of the LAN9512 chip, causing a "fight" between the two LDO regulators.

I did not expect the OP to measure the 1V8 generated by the LAN9514, just remarked it because a short there would explain why the 3V3 LDO would need to supply much more current than it normally does, and why the LAN9514 chip does not work.

as far as I know, the LAN9514 is still fed a 25MHz signal from the SoC, just like previous models.

I would suggest the OP's PI is dead, and should be returned under guarantee, or a new one bought.

it will be almost impossible to help him to fix it.

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mahjongg
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Re: repair raspberry pi 3 b

Wed Jun 06, 2018 4:42 pm

mohammad462 wrote:
Sun Jun 03, 2018 7:46 pm
There is one thing that is very strange for me.
When you connect the power supply, both the usb and the lan will be energized for a second.
How do you know that?

mohammad462
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Re: repair raspberry pi 3 b

Wed Jun 06, 2018 7:38 pm

I can not send it back because it has no warranty.
So I have to fix it.
From there, I know that the mouse LED is lit for a second. Also, the lan LED also lights up.

mohammad462
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Re: repair raspberry pi 3 b

Thu Jun 14, 2018 5:22 pm

Is there a burning capacitor?
Or a simple transistor?
Guess what parts might be burned?

mohammad462
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Re: repair raspberry pi 3 b

Sun Aug 26, 2018 5:25 pm

Has anyone found a solution to my problem? :|

fruitoftheloom
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Re: repair raspberry pi 3 b

Mon Aug 27, 2018 4:19 pm

mohammad462 wrote:
Sun Aug 26, 2018 5:25 pm
Has anyone found a solution to my problem? :|

Yes buy another Raspberry Pi SBC.
adieu

My other Computer is an Asus CS10 ChromeBit running Chrome Operating System.
HP Envy 4500 Wireless Printer supported by HPLIP software in Raspbian Buster.
Raspberry Pi Model 2B v1.1

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mahjongg
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Re: repair raspberry pi 3 b

Mon Aug 27, 2018 5:46 pm

You still don't seem to have a good idea what my question "where did you measure the 5V" means, I mean did you measure it on the power supply, or on the powered raspberry PI, on a point after its poly fuse. An under voltage indication is a clear sign that the full 5V does not reach your PI, main reason is a weak power supply cable, another possibility is a semi-burnt polyfuse that has developed some resistance.
Without the full 5V, many USB devices wont work, which is why you might think the PI is defective.

measure 5V between a well define ground point, (any of the connectors with a metal outer shell have these metals connected to GND), and on both sides of the poly-fuse, if the voltage on one end of the polyfuse is different from the other end the polyfuse has gone bad.
PI3B Polyfuse.png
PI3B Polyfuse.png (108.21 KiB) Viewed 1489 times

mohammad462
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Re: repair raspberry pi 3 b

Mon Aug 27, 2018 7:56 pm

This polyfuse you said does not have my device.
But I found it and it was exactly 5 volts. In photo 1.
But a weird test.
In the second photo, I connected the 1 and 2 with a single LED, it turned on, while the USBs were also energized and the mouse light turned on.
Image
Image

drgeoff
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Re: repair raspberry pi 3 b

Mon Aug 27, 2018 9:35 pm

@mohammad462

That is not the polyfuse. The polyfuse is on the underside of the board.

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