Author Topic: PCB not starting after Soldering  (Read 617 times)

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Offline Will_I_am344

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PCB not starting after Soldering
« on: Fri, 11 September 2020, 05:50:33 »
Hi. I tried some soldering on my pcb. Before soldering it booted correctly and all keys worked (tested with tweezer), and the underglow started.

After soldering some of the switches I tested again and the underglow did not start, neither could I activate any key with tweezer nor switch. However, my computer recognizes that an USB device is connected when I plug it in.

I failed one of the joints close to the usb-c because the solder got attracted to the port instead of the switch because they were so close and I aimed the it wrongly. I tried to remove it but it didn't seem to work.

Another thing I thought of was maybe it was the flux that shorts the pcb? I tried cleaning it with 99% ipropoyl alcohol and boot it again but still no response.

The reset button on the pcb works! It successfully restarts. However, nothing else still works. Which makes me hope that the fault is not with the USB-C port. What do you think?

ANY HELP is appreciated! Hopefully I don't have to throw it all away :(

Offline PJE

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Re: PCB not starting after Soldering
« Reply #1 on: Fri, 11 September 2020, 06:08:38 »
Looks like you shorted one of the switch pins to the USB connector shell which is grounded when plugged into the PC. This may pull the CPU power down, preventing correct operation.

Remove the solder bridge, and retest. Hopefully there will be no lasting damage.


Offline Will_I_am344

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Re: PCB not starting after Soldering
« Reply #2 on: Fri, 11 September 2020, 06:25:34 »
Thanks for the answer! How would I go about removing the solder bridge?

I go in with a heated solder iron and vacuum up the rest? I tried doing that but not successfully :(

How could I go about it?

Offline PJE

  • Posts: 19
Re: PCB not starting after Soldering
« Reply #3 on: Fri, 11 September 2020, 06:36:33 »
You would need either a solder sucker, or wick to get rid of as much solder as possible. It is possible to use a clean soldering iron tip to take off solder, but you risk overheating the board.

There should be no connection from the switch pin to the connector. Id use a multimeter to test continuity between the pin and the connector shell.


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Offline suicidal_orange

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Re: PCB not starting after Soldering
« Reply #4 on: Fri, 11 September 2020, 06:37:39 »
Thas's pretty much it, a sucker or soldering braid.  At a push you can try pulling through the solder repeatedly in the same direction with the hot iron while blowng the same way (only when pulling) but really components aren't designed to be heated for long.  If you have some fairly thick stranded wire that can work as braid - spread the strands a bit then put it on the solder and heat through the wire, if you have flux coat the wire in that to help it draw up the solder.
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Offline Tactile

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Re: PCB not starting after Soldering
« Reply #5 on: Fri, 11 September 2020, 09:19:28 »
I see some joints which could be better. They may have a connection but could fail considering that a keyboard gets literally banged on constantly. Have a look at this web page for some good advice.

Offline Will_I_am344

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Re: PCB not starting after Soldering
« Reply #6 on: Fri, 11 September 2020, 09:26:19 »
desoldering worked, thanks alot for thelp!