sim300 +cpin:ready again after few minutes not ready

dear frnds,

when i start the sim300 module it gives cfun:1 and +cpin:ready and detects the SIM (2.8V at 1st pin) after few secs it responses +cpin:not ready and starts blinking.when i restart the module again the above process continues.

the module body is grounded.
i used 10k pull up from 6th pin to 1st pin of sim
220nf capacitor at 1st pin
Vbat is 4.2V & 2A current with 100uf tantalum and 100nf capacitors.
when power on the voltage at vdd_ext is 2.91 and intially 2.8v at sim_vdd but later it comes down to 0.04v.

please help me in solving the problem.

Hi,
If possible send the schematic of the same. and few queries I required.
1) Which regulator IC do you use to give supply?
2) add 2 nos. of 470uF capacitor minimum. and check.
3)Put your multimeter probe on VBATT and keep checking from reset of module to problem occurred. (Check for any voltage changes during these period).
4) If everything ok then check if it is written 64K on your SIM card. if 64K written then
shoot command ATi and paste the response here.
Probably looking like current issue .

hi shailesh,

The sch and modem response log files are attached.
i am using external DC power supply (Range:0-30V/2A), set the voltage to 4.23 and current to max.
tried using 2 (470uf/10v) capacitors and tried removing and replacing all possibilities of capacitors at different levels,but the result is same as earlier.
i did not find any voltage changes at VBAT used both multimeter and oscilloscope.
on SIM card its written 32k.
also checked the current on power supply module display.

terminal log file attached

Can you tell me in details about your projects

Dear Sri....
have analyzed your schematic and suggested some points please do changes into it.

http://rapidshare.com/files/354680365/1266563327_22457_FT31231_sim300.rar.html

hi shailesh thanks man,problem solved,now its working ok...the problem was in voltage and current paramters.

ALL The Best, but can you please tell me how did you analyze the problem? write it here so it will be helpful to everybody in future to work as Case study.

Thanks Agian

sri.. its good to share your problems but its even better to share your solutions

Hope you will post.

I need a hand...I using the SIM300 with the OLIMEX's PIC-GSM, and a while ago I was working pretty good with that modem, I was doing everything...making calls, sending messages and receiving it...after some days, a noticed that the modem had a strange behavior, so I checked it and it said the CME ERROR 10:SIM NOT INSERTED, so, I think is almost the same problem posted here....so anybody...may share with me the solution...how it was solve? Can you tell me at [email protected] thanks to you man.....