ospelayo
Posts: 4
Joined: Wed Oct 12, 2016 3:19 am

B+ Not Booting Anymore

Thu Oct 13, 2016 1:48 am

Hi There,

My pi B+ worked fine for few months but now it isn't anymore. When it was booting fine, red power led stays on while green act led flashes while booting (suggesting that it is reading from the card). The last time I remembered doing was apt-get upgrade and could have some errors but did not take note of it. Afterwards, it cannot boot anymore. I know that my pi is faulty because I tried to replace the power supply (2) and sd cards (3) to no avail. With only the sd card and the 5v supply only connected to my pi, the red and green leds stay forever. I tried several things like applying a bit of pressure to the card hoping that would make the green led blink at least once but it stayed on brightly. This is the same thing when you remove the sd card and power it up.

Is there anyone here who knows how to resurrect my pi? I can solder well and can read schematics. I tried resoldering the sd card port portion and checked whether any pins were shorted or open but still not working. TIA. :)

wh7qq
Posts: 1475
Joined: Thu Oct 09, 2014 2:50 am

Re: B+ Not Booting Anymore

Fri Oct 14, 2016 8:00 pm

With power off, remove SD card and try to reformat with SDFormatter (windows or mac) or gparted (linux). Reload fresh Raspbian or Noobs on the card and try again. If reformat does not work, get a new card from a reputable source and try that. Check with h2testw or f3 to be sure card is legit...counterfeits abound. Powering down before all the flashing stops or removing an SD card before powering down may bork the SD card.

Some B+ and Pi 2 SD card holders (like mine) no longer latch the card in place and it is necessary to retain them mechanically. A rubber band is a good temporary fix but several thin plastic wire ties together will provide a more permanent fix.

ospelayo
Posts: 4
Joined: Wed Oct 12, 2016 3:19 am

Re: B+ Not Booting Anymore

Sat Oct 15, 2016 4:58 am

thanks wh7qq, unfortunately, i inserted 3 different working sd cards, one is class 10 32gb, used sd formatter, used raspian, raspian lite, noob, noob lite, used 2 working 5V 2A power supply but still the card won't boot. that is why i suspect my pi is faulty. :(

i resoldered the sd card portion, checked that there is still continuity from pcb pads to every pin that supposed to touch the sd card golden pads, removed the heatsink to avoid shorts surrounding the bga ic, and inspected that there is no visual issue on my pi, to no avail.

Any one here captured the voltage at every test point on the pi when turned on without any sd card inserted? I just want to compare it with mine. Currently I don't wanna buy a new one. :(

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davidcoton
Posts: 5336
Joined: Mon Sep 01, 2014 2:37 pm
Location: Cambridge, UK
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Re: B+ Not Booting Anymore

Sat Oct 15, 2016 8:39 am

ospelayo wrote:Any one here captured the voltage at every test point on the pi when turned on without any sd card inserted? I just want to compare it with mine. Currently I don't wanna buy a new one. :(
You can measure the voltage at the supply test points, the correct values are obvious. You can identify these points from the (partial) circuit diagrams on this site.
The voltage at other test points (ones with digital clocks or signals) are not very useful as a diagnostic, you need an oscilloscope to monitor them. The correct clock waveforms should be obvious (at least for those included on the circuit diagram), beyond that I don't know of any references for correct waveforms.
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