ranjitiyer
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After soldering a pin header, can't flash LED anymore

Sat Jul 13, 2019 10:42 pm

Hello Group,

Sorry if this has been asked a million times, I'm be happy to be redirected/chastised ;)

I soldered on a 40 pin male header on my Pi Zero W and since doing that I don't get 5V out from Pin 2 and Pin 4 and can't flash an LED from a GPIO pin either. I checked with a Voltmeter and don't see a reading on the supply pins. Not sure if I burned anything out, although the soldering looks good and can't see any evidence of two pins accidentally shorting.

Thanks :)
Ranjit

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HawaiianPi
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Re: After soldering a pin header, can't flash LED anymore

Sat Jul 13, 2019 11:23 pm

Got pictures?

Hard to say without seeing what it looks like, but if it worked before you soldered the header on, then something was shorted, overheated, a trace was damaged, or you accidentally removed a component (a tiny SMT resistor or capacitor fell off when soldering nearby).

If it does turn out to be dead, you can get the Pi Zero WH with headers pre-installed for only 4 bucks more.
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ranjitiyer
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Joined: Sat Jul 13, 2019 10:05 pm

Re: After soldering a pin header, can't flash LED anymore

Sat Jul 13, 2019 11:35 pm

Thanks for your response. I've posted some pictures here.
https://photos.app.goo.gl/mmh6RXL3ymv1CWPKA

Overheating or shorting may be. Appreciate you taking a look!

Thanks,
Ranjit

Love your signature with the browser analogy :)

BespokeTech
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Re: After soldering a pin header, can't flash LED anymore

Sat Jul 13, 2019 11:53 pm

Sorry to say but those soldered joints are very poor. The solder clearly hasn't flowed from the pin to the pad on the PCB. When soldering you need to ensure both the pad and the pin are sufficiently heated before applying solder to the joint.

I would recommend getting hold of some Veroboard if you can https://www.amazon.co.uk/Copper-strip-p ... B01C5TB3L8 to practice with first.

plugwash
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Re: After soldering a pin header, can't flash LED anymore

Sun Jul 14, 2019 12:07 am

The good news is I don't think you have destroyed anything, I just don't think you have made a successful joint to the pads. Far from burning stuff I don't think you have used enough heat. Also on many pads I don't think you have used enough solder.

You need to keep the heat on until the solder flows around the joint, sometimes you need to scrape the surfaces a little with the tip of the iron to break through surface oxidation. Some people find it helpful to add extra flux, though that can be a bit stinky.

pcmanbob
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Re: After soldering a pin header, can't flash LED anymore

Sun Jul 14, 2019 9:45 am

I would suggest you first go look at one of the many soldering tutorials on you tube to see how it should be done, and then practice with some strip board and resistors which are cheap enough to practice with, before attempting to solder the header on to the pi again.

https://www.youtube.com/results?search_ ... g+tutorial
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IOTON
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Re: After soldering a pin header, can't flash LED anymore

Mon Jul 15, 2019 5:03 am

plugwash wrote:
Sun Jul 14, 2019 12:07 am

You need to keep the heat on until the solder flows around the joint, sometimes you need to scrape the surfaces a little with the tip of the iron to break through surface oxidation. Some people find it helpful to add extra flux, though that can be a bit stinky.
I think it's not necessary. Pi zero W board has excellent PCB quality and immersive gold coating. I soldered 100+ w/o any problems and any additional flux.

I used Asahi 52269. Soldering iron at 350 degrees celsium.

If you want to know something about pin header soldering problem, try to solder it on Banana Pi m2 zero 8-) .

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