Soldering problem - need help !

User avatar
phinix

10 Mar 2019, 15:15

Hi guys.
I need help. I was working on my first ever re-soldering project - I desoldered Varmilo VA69M and soldered Tealios on it.

However, as I don't have an soldering experience, I messed up few places and now 3 switches don't work.

I'm wondering if this can be fixed or did I killed £170 worth of board... :(

Please see those images, first one is up arrow - I think, I THINK... when I was taking off old switch I also took out that small ring that was on the pcb. Then I noticed that this thin long thingy - don't know how you call it - is coming off. It looks like a thin copper "route"?
I soldered it to that spot, but switch still not registering.

Second photo is "\" and "Z" - both not registering. One has lost this small ring on pcb, but other one was fine.
Please ignore those burnt holes over the switches - those were leds - I was not able to get rid of them easily:(
I know...baaaad soldering...

Is ther a way to fix those? Can I somehow "re-wire" them?

Image

Image

User avatar
vvp

10 Mar 2019, 19:23

phinix wrote:
10 Mar 2019, 15:15
Please see those images, first one is up arrow - I think, I THINK... when I was taking off old switch I also took out that small ring that was on the pcb. Then I noticed that this thin long thingy - don't know how you call it - is coming off. It looks like a thin copper "route"?
I soldered it to that spot, but switch still not registering.
The thin long thingy is called a wire or a trace. The wire ends with "ring" you lifted. The "ring" is called a pad (or one side of the pad). The pads can be SMD (for surface mount parts) or THT (for through hole parts like e.g. switches). THT pads have 3 parts top "ring", bottom "ring" and centre copper "tube" called through hole plating. Notice that a through hole plating also serves as a connection between wires on the top and the bottom part of the PCB through the "rings".
Probable problem:
* you lifted the "ring" -> you may not have proper connection between the top and bottom wires
* you lifted the wire/trace as well -> maybe the connection the wire provide is not there

I would desolder the switch, remove the lifted wire, check the other side of the PCB whether the THT pad was connecting some wires. If yes, I would use a thin wire (e.g. Ø 0.2 mm) to provide an alternative connection. Often the hole is big enough so that the wire can be routed through it and the through hole part pin can still be inserted into the same hole. Then I would soder back the switch to the wire.
phinix wrote:
10 Mar 2019, 15:15
Second photo is "\" and "Z" - both not registering. One has lost this small ring on pcb, but other one was fine.
Please ignore those burnt holes over the switches - those were leds - I was not able to get rid of them easily:(
Probably the same problem as above for the lost "ring". Notice that the burned LED holes may have provided a connection between wires on different sides of the PCB. That can be problem too. The other switch may have just a bad connection or it is OK and does not work because the switch with lost "ring" or the burned LED holes (if they were connecting wires on different PCB sides).

User avatar
phinix

10 Mar 2019, 20:05

This is now fixed, thanks for your reply.
Happy days! :)

User avatar
vvp

10 Mar 2019, 21:48

Cool.

Use less solder next time so that the joint surface is concave. This allows you to see whether the solder weted the joints properly. Improperly weted joints are not visible if too much solder (convex surface) is used.

Post Reply

Return to “Workshop”