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GPRS/GSM SIM900 Shield development board not working at all
Posted: Fri Jul 25, 2014 1:34 pm
by bitkalipso
Hello,
I bought this shield from ebay but it seems to be broken. Fist I contacted the seller because The SIM900 chip seemed washed out (I attached 2 photos), at that time I only powered up the board from Arduino and I noticed that only the green LED is ON, I pressed the reset button several times but the other two LEDs were still off.After a while I bought a 5V 2A power supply, but the board still wasn't working.It only powers ON (green LED on the other two stays off), I also tried to communicate with the chip but it never responds. The seller asked me to post this issue here, but my opinion is that the SIM9000 chip was damaged - before or during the soldering.
Best regards,
bit
Re: GPRS/GSM SIM900 Shield development board not working at
Posted: Fri Jul 25, 2014 6:12 pm
by Irene
Dear friend,
We are sincerely sorry for the inconvenience caused you.
But I have to tell you that all our products are 100% tested before shipping out.
We are always on your side and trying our best to help you to solve it because we are serious sellers.Your satisfaction is our pursuit.
As you know that the international shipping situation is so complicated and some deliverymen are rude to the parcles.All the products are out of our control after we shipped it.Appreciate you could understand.
Let's get to the point now.Please be a little patient and try the following steps:
1.Please test the voltage between key1 and GND,Key2 and GND.
2.Use a Dupont jumper cable to connect the pin1 and GND,make sure that it should be lasted over 1s.Then check the led's condition.
3.By the way,did you press the switch up to one second?
Please tell us the results after you tested.We will confirm it and give you further solution.
Look forward to your early reply.
Best regards
Re: GPRS/GSM SIM900 Shield development board not working at
Posted: Mon Jul 28, 2014 5:26 am
by bitkalipso
Hello,
The voltage between key 1 and GND is 3V,between key2 and GNS is 0V,
I did connect pin one to GNDfor more than one second but the other two LED2 are still off. I also pressed the reset button for more than one second but still nothing.
Best regards,
bit
Re: GPRS/GSM SIM900 Shield development board not working at
Posted: Mon Jul 28, 2014 2:05 pm
by Irene
Dear friend,
Now we have confirmed that there is no problem with the PWRKEY.
Then please be a little patient and test if there is some problem with the sim chip and the LED module.
1.Test the voltage between the pin52 and GND,pin66 and GND.
2.Test if there is 5V voltage output from the led.
Test the resistence of the highlighted "4.7k",and check the resistor carefully to see if it is not soldered well or if there is a bridge between them.
Please tell us the result after you tested.
Appreciate your patience and understanding.
Best regards
Re: GPRS/GSM SIM900 Shield development board not working at
Posted: Wed Jul 30, 2014 1:13 am
by bitkalipso
Hello,
The voltage between pin52 and GND,pin66 and GND is 0V in both cases
The output from the LED is 5V,
The resistors seems to be fine, the only difference is that instead of 47K there are 20K resistors.
Best regards,
Bodian
Re: GPRS/GSM SIM900 Shield development board not working at
Posted: Wed Jul 30, 2014 1:38 pm
by Irene
Dear friend,
Our customer service will contact you.
Wish you a nice day!
Best regards