No Power to Pi Zero

cannfoddr

New member
Apologies for English ...

I have just put together a mini using a prebuilt board I obtained some time ago through this forum. I have run through all the recommended setup tests and see all the correct test voltages.

When I mount the Pi and apply power I see the screen menu but nothing else. I don't think the Pi is even powering up - I think I should be able to see the LED through the plastic surround of the board hole - I can when I apply power directly to pi when it is not mounted. I can see 5V on 5V pin of the Pi.

If I unmount the Pi and power directly it powers up and LED lights - maybe the LED is not illuminated when the board is powered via GPIO.

I saw a problem further down the forum about changing some settings in boot.txt - I will try this next and maybe everything is OK
 

s.ochs

BOFH
Teammitglied
Hi,

the RPI LED should always be lit when the power is on.

Where exactly did you measure the 5V on the Pi when plugged in? Can you please take a photo of the board and the Pi?
You may have a short circuit on the board, but this only occurs when the Pi is attached. And therefore it does not start.

Best regards
Steffen
 

cannfoddr

New member
Steffen

Here is shot with it installed - I can pull out later and get the reverse side.

IMG_0522.jpeg

I measured on the back side of the GPIO connector on the Pi - got 5V between 5V pin (bottom left) and the ground 4 pins up.

Have tried two different Pi Zeros - one I soldered the GPIO and one was factory soldered.

I have removed all the probe connections - makes no difference

When I dismantle I will try a bench test without the XLR connections

Adrian
 

cannfoddr

New member
I have taken it all apart and even with nothing plugged in apart from Pi and Power I cannot get an LED.

Here is the mainboard front and back
IMG_0524.jpeg IMG_0523.jpeg

The first and second 5V on the GPIO with the ground (3rd) GPIO Pin:
IMG_0527.jpeg IMG_0528.jpeg

Bottom Right GPIO I think is supposed to be 3V - its not!
IMG_0529.jpeg

Unless anyone has better suggestions I am going to reflow all my soldering on the mail board in the somewhat blind hope that I have abad solder joint somewhere,
 

Anhänge

s.ochs

BOFH
Teammitglied
I suspected the solution is very simple: the Pi is plugged the wrong way round.
[automerge]1580845923[/automerge]
You need to unsolder the header and solder it to the other side of the pi board. These are the pins you wanted to measure, but they're on the wrong side.

IMG_0527.jpeg

I hope it didn't hurt the Pi .
 
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cannfoddr

New member
I ordered a factory Zero WH with header and its soldered exactly this way are you saying when mounted I should be able to see the top surface of the Pi?
 

cannfoddr

New member
Thanks to everyone who has helped I now have a working Mini V2 - had a bad solder joint on the power pins for the display that took a while to track down. Had to force the Pi to update the screen when I got it working and so far everything looks good.
 
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