Module PCB: solder side problem?


Hi everyone! I’ve soldered together the All-In-One Module PCB but connecting it to the pi makes the pi not boot.

I think the problem may be that I soldered the connectors and the GPIO pins on the bottom of the board… got confused from the photos. Can anyone confirm before I attempt to remove them and resolder?


Hi @Fitz!

My friend, PCBs are not generally reversible. In fact, a reversible PCB is very strange and really difficult to design!!! Of course, Zynthian AllInOne module is not, nor the controller modules. So … you have to solder every part in the right place and side. Unless you know very well what are you doing, nothing will work if you solder the connectors in the bottom side, specially the GPIO 40-pin connector.

Kind Regards,


Please, could you specify witch photos cause the confusion? I would like to improve it …


Thanks for your reply. That explains why it doesn’t work!

On the photo showing the completed module:
To me, it looks like the resistors, diodes and chips have been soldered on the upside/labeled side, but the GPIO pin and connectors look too close to the board, so I soldered them on the bottom/unlabeled side.

It would be good if you could tell me which side is correct! I may have missed this information when I followed the wiki :upside_down_face:


Fernando thought, that you had mounted the parts on the bottom side as well.

So, you mounted them correctly, but you need to turn everything around and solder it at the bottom side.
Bend the legs a little, so that they keep the position.

But I don’t know, if you have to unsolder it.
Can’t you solder the bottom side additionally?

You are sure, that esp. the MCP is soldered ok and you didn’t connect two legs by accident?


Hi @Fitz!

Could you send some photos from your module? Perhaps this helps to understand what you did exactly :wink:



I think that what you see is solder that has filled the component hole. This happens on multi layer boards. You solder on the solder side, but the through hole gets hot enough so that solder flows up, and will appear on the component side.



I soldered the wrong side for the components. If you make a note on the wiki to solder on the opposite/bottom side this might make it easier to understand.

I’ll keep the components in place and add more solder to the bottom. Hopefully this will fix it!

Thanks for your help


Actually this is common sense.


Hi…i am a new user here. As per my knowledge solder bridging occurs when two solder joints connect, forming an unintended connection that can lead to short circuits on your board. As you can see in the image above, the first two pins on this IC have bridged together.

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A solder sucker is the answer to your problem. . . .

Solder Sucker