fona 800 gnd soldering issue

[acambiani]

Hello

I bought in the last 3 months over 30 of your fona800

In all of your device there is a problem in soldering the GND pad, and with vibration the solder get away

now the solution for me is a double solder, upward and downward for stop the pin but after 30 pieces with all the same problem only in the GND pad I think that you have a problem in production process.

[adafruit_support_mike]

We haven't seen any other reports of trouble in that area.

Could you post a photo showing the area where the solder connections are failing please? 800x600 images usually work best.

[acambiani]

It's strange because I bought the fona from different resellers.

Now I have other 10 fona bought from RSComponents with the same issue, Only on GND pad

I use Lead free solder, no problems with other pad, only with gnd pad the solder not attach very well.

In the uploaded image you can see the pad at the right and the left without any problem, the gnd is not very well connected.

[adafruit_support_mike]

Hmm.. that's really strange.

If anything, that GND pad should have a better connection to the substrate than the pins on either side of it. The hole is through-plated, and the pad has thermal traces to the copper foil on either side of it.

I don't remember ever seeing a FONA's pads delaminate like that, which suggests something is happening in the environment where you're using them. You mentioned vibration, and if multiple boards have failed in the same system, it strongly suggests the system is applying unusually high repetetive strain to that pin.

[acambiani]

the boxs with inside the fona800 are fixed to the walls, so the vibration are not massive but only natural vibration of buildings.

tell me how I can help you for find the issue, maybe is a problem of particular stock sold in Europe.

I try today with cleaning the GND pad with Isopropyl alcohol and the situation is better, now the solder seems attached to the pad.

For me is not a problem because I solved the problem with a double solder (on back and on top), I opened this post for you, because is a recurring problem with your Fona800.

[cry4brk]

You should be using a soldering iron with a little more power. The GND PAD is attached to the ground plane. If you have a weak soldering iron, when you touch the pad, the temperature goes down quite fast. So nothing wrong with the fona itself. It's your soldering iron that requires an upgrade.
You may have not noticed, but you can't get solder wire with lead in Europe anymore. (the one that melts at lower temperature). All you can get now in lead free and it requires a higher temperature.

[adafruit_support_mike]

We’ll keep an eye open for other reports of similar issues, but haven’t see any others yet.

There are always two suspects for any failure: the part that actually failed, and the system it was connected to when it failed. If the same part fails when connected to multiple different systems, it suggests a problem with the part. If the multiple parts fail in the same system, it suggests a problem in the system.

Your report gives us information about one system. If we see reports of similar failures in other systems, we’ll know we need to take a hard look at that part of the board.