Sim900 Reset Problem

[rmrps]

Hi Friends I am sim900 module to send sms and gprs usage when i am power on the module without inserting simcard its working fine that is no reset. But when i am inserting card its keep on reset for every 5 seconds once i am giving 3.9v for the Vbat pins please help me how to resolve this problem thanks in advance

 

[ADGAN]

I'm also facing a similar problem. I'm using a TC35 Siemens GSM modem. After the network initializes, the power supply shows that there is a short circuit. (Indicator bulb for short circuit of the power supply switches ON & OFF rapidly) When I remove the SIM it looks fine.

 

[amol_shah]

It could be because the power supply is not able to provide the required current. What is your transformer/adapter rating? Also add a large value of decoupling capacitor abt 470uf.

 

[Golden Electronics]

Increase Battery Capacity by paralleling & also provide cap of 2200 or 4700 uf

 

[rmrps]

Thanks for the reply friends