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Faulty 3G Fona Module??
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Please be positive and constructive with your questions and comments.

Faulty 3G Fona Module??

by Agriculex on Tue Oct 20, 2020 11:55 am

I have two 3G Fona Module (North America version). The first one bought directly from Adafruit 8 months ago and the second module was bought about 2 month ago from Digikey.
Both module have "PCB adaptor" soldered to it to use a FFC cable & connectors to interface with my custom made Arduino board. The code that works with the module is taken from the Adafruit_FONA library.

The first module bought directly from Adafruit worked flawlessly with my Arduino code and easily connected to the cellular network. However, the second module from Digikey is NOT working as expected. With the same SIM card, antenna, Arduino, and code, it seems to be having issues with network connection.

Now, it does connect to the network after a while (NET LED flashes 800ms) but it's in a useless state. Whenever I open or close the serial monitor, both the PWR and NET LED turns off for a few seconds and turns back on and stays on. During that time, I keep getting the timeout and couldn't find Fona message on the serial monitor. Then the NET LED starts flashing 800ms.

I'm assuming there is a defect with the module bought from Digikey. Anyone else experienced this issue or knows what's going on?

Agriculex
 
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Re: Faulty 3G Fona Module??

by mikeysklar on Wed Oct 21, 2020 3:16 pm

@agriculex,

Are you using our Lipo battery with each unit? We do have an entry in the FAQ about flakey auto-shutoff behavior with 3rd party batteries. I didn't see a mention that you had been testing with a battery or moving between devices.

https://learn.adafruit.com/adafruit-fon ... akout/faqs

Would you mind uploading a photo of your wiring so we can see if anything seems out of place.

mikeysklar
 
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Re: Faulty 3G Fona Module??

by Agriculex on Wed Oct 21, 2020 4:51 pm

@mikeysklar

For the LiPo batteries I used, they should be from Adafruit as they're bought from Canada Robotix who is an Adafruit Distributor. With the first 3G module I bought (that worked fine without any issues), it worked even without a LiPo battery. As a result, I initially tried the second module without the LiPo battery. Even when I tried using the second module with a few different LiPo batteries connected, it was still the same problem.

I took photos of my setup. Note that my first module worked on the same setup as shown in the photos even without the LiPo battery. For the wiring, module is connected to the a custom Arduino Mega board I made through a FFC. The FONA_RX, FONA_TX, and FONA_RST pin is connected to D11, D10, and D12 respectively. They share the same 5V and GND line.

IMG_4658S.JPG
Overall Setup
IMG_4658S.JPG (117.99 KiB) Viewed 384 times

IMG_4659S.JPG
Closer Look on the Module
IMG_4659S.JPG (108.05 KiB) Viewed 384 times

IMG_4661S.JPG
Module During Operation (Powered ON)
IMG_4661S.JPG (104.91 KiB) Viewed 384 times

Agriculex
 
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Joined: Fri Mar 06, 2020 3:22 pm

Re: Faulty 3G Fona Module??

by mikeysklar on Fri Oct 23, 2020 2:22 pm

@Agriculex,

Let's back up a step and remove you custom board / code and try a basic network connect test with the new board.

https://learn.adafruit.com/adafruit-fon ... twork-test

Our FAQ is loaded with the LiPO battery being necessary to power the FONA so we should stick with that for now.

mikeysklar
 
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Joined: Mon Aug 01, 2016 8:10 pm

Re: Faulty 3G Fona Module??

by Agriculex on Tue Oct 27, 2020 10:57 am

@mikeysklar

So I called Digikey and got a replacement unit. Tested the replacement unit on a breadboard with a Sparkfun Pro Micro. Got the same issue initially until I changed the baud rate in Serial.begin() from 9600 to 115200. However, this change didn't do anything for the problematic (second) unit that started this whole thing.

IMG_4672S.JPG
Breadboard Setup w/ the Replacement Unit
IMG_4672S.JPG (883.61 KiB) Viewed 357 times


After comparing the two units, I did notice the problematic unit has a different SIM card holder and placement of the SIM card during insertion is slightly different as well. I'm guessing that might be the issue. Anyways, my issue is solved with the replacement module.

IMG_4673S.JPG
SIM Card Holder
IMG_4673S.JPG (1008.49 KiB) Viewed 357 times

IMG_4675S.JPG
Different Hinge System on SIM Card Holder
IMG_4675S.JPG (903.2 KiB) Viewed 357 times

Agriculex
 
Posts: 7
Joined: Fri Mar 06, 2020 3:22 pm

Re: Faulty 3G Fona Module??

by elin05 on Wed Mar 31, 2021 3:24 am

I’ve seen quite a few posts here about bad FONA 3G boards coming from Digikey. I am also experiencing the same issue.

My FONA 3G board purchased from Adafruit has no issues. My FONA 3G board purchased from Digikey has the following issues:

At first, it never responded to AT commands. I probed the FONA 3G Tx pin during the AT requests and saw no activity.

After some more troubleshooting, the Power and Network LEDs no longer lit up. Turns out the bird could no longer power on. With a direct USB connection, holding the Key button for 5 seconds did not turn on the board. The Power and Network LEDs would briefly flash and were very faint. They no longer turn on.

Can Adafruit do some quality checking on Digkey’s batch of FONA 3G boards? Is there a way I can get an RMA on my board even after I’ve soldered and desoldered the headers?

elin05
 
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Please be positive and constructive with your questions and comments.