De-soldering Button PCB from Raspberry Pi

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De-soldering Button PCB from Raspberry Pi

Post by wattwatt » Wed Feb 14, 2018 12:02 pm

I finished Soldering my PCB and Pi together, all test pads were a "Go". I went to test boot it... a couple blinking lights on the Pi, then nothing. Nothing on the LCD or a monitor through the HDMI.

After some reading around the forums to match my symptoms with someone else's, it seems I have grounded my power. I put too much solder into the VCC hole and it seems to have leaked to the other pads next to it. Testing the VCC to any GND pad is reading continuity, which isn't good.

Since, for the time being, Helder is sold out of PCB's, my question is: Does it seem possible to de-solder the Raspberry Pi from the Button PCB without ruining the pads underneath? Or is this a lost cause at this point? I was thinking of employing everything from a heat gun, to one of those little spring solder-suckers, and copper mesh. Just don't want to ruin the Button PCB (not too worried about the Pi, thats pretty disposable at this point).

I only do these types of things at a Hobby level, so any advice would be helpful.

Thanks

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Re: De-soldering Button PCB from Raspberry Pi

Post by Helder » Wed Feb 14, 2018 2:37 pm

Heat gun that isn't too wide meaning one in a hot air rework station can do it. What I do it hang the pi off a table and put something with weight on the button pcb and heat the GPIOs slowly across them all and keep doing that till it starts to melt and gravity will do the rest.
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Re: De-soldering Button PCB from Raspberry Pi

Post by moosepr » Wed Feb 14, 2018 3:32 pm

Yeah I second that with a super fine heat gun. I have successfully removed a pi. I went down the pins with an iron and solder sucker first and removed as much of the solder as I could. I then smothered it with flux and gently heated it
Get a small cheep LCD in your project https://www.sudomod.com/forum/viewtopic.php?f=22&t=2312
Wrap it all round a battery https://www.sudomod.com/forum/viewtopic.php?f=13&t=2292
Or use a custom PCB to make it really small https://www.sudomod.com/forum/viewtopic.php?f=13&t=2512
or make it really really really really tiny!! https://www.sudomod.com/forum/viewtopic.php?f=13&t=2919

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Re: De-soldering Button PCB from Raspberry Pi

Post by wattwatt » Wed Feb 14, 2018 8:26 pm

Thanks! will do that and see what happens.

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Re: De-soldering Button PCB from Raspberry Pi

Post by moosepr » Thu Feb 15, 2018 3:34 pm

Just direct the heat away from the pi. Don't want to go desoldering the CPU 🙈
Get a small cheep LCD in your project https://www.sudomod.com/forum/viewtopic.php?f=22&t=2312
Wrap it all round a battery https://www.sudomod.com/forum/viewtopic.php?f=13&t=2292
Or use a custom PCB to make it really small https://www.sudomod.com/forum/viewtopic.php?f=13&t=2512
or make it really really really really tiny!! https://www.sudomod.com/forum/viewtopic.php?f=13&t=2919

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abrugsch
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Re: De-soldering Button PCB from Raspberry Pi

Post by abrugsch » Fri Feb 16, 2018 3:39 am

moosepr wrote:
Thu Feb 15, 2018 3:34 pm
Just direct the heat away from the pi. Don't want to go desoldering the CPU/GPU/RAM 🙈
FTFY

wattwatt
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Re: De-soldering Button PCB from Raspberry Pi

Post by wattwatt » Sun Feb 18, 2018 3:19 pm

So I got the Pi up and seemed to lift the top portion of a few pads. I tested them with a multimeter and they still work. Any thoughts on if this would work to re solder over?

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Re: De-soldering Button PCB from Raspberry Pi

Post by rodocop » Sun Feb 18, 2018 4:09 pm

You can re solder them. And check continuity after. Worst case you'll just need to run jumper wires to the test pads that correspond to lifted gpio pads. It doesn't look to bad.

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Re: De-soldering Button PCB from Raspberry Pi

Post by moosepr » Mon Feb 19, 2018 2:06 am

i did a test removal yesterday without sucking the solder first. It took much longer to get the heat to soak in to all the solder, and i ended up loosing a few pads from the pcb
Get a small cheep LCD in your project https://www.sudomod.com/forum/viewtopic.php?f=22&t=2312
Wrap it all round a battery https://www.sudomod.com/forum/viewtopic.php?f=13&t=2292
Or use a custom PCB to make it really small https://www.sudomod.com/forum/viewtopic.php?f=13&t=2512
or make it really really really really tiny!! https://www.sudomod.com/forum/viewtopic.php?f=13&t=2919

wattwatt
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Re: De-soldering Button PCB from Raspberry Pi

Post by wattwatt » Sun Feb 25, 2018 5:40 pm

After attempt #2, I got the minty pi up and running with just the button pcb and Pi. Even got Doom running. Went to assemble everything else, charged the battery, and now I cant get it to start. All I get is the screens backlight turning on and no green light on the Pi.

Does everything look right here? (the discoloration on the Pi is just flux)
Any thoughts?

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