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SIM Reader test with a meter?
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

SIM Reader test with a meter?

by HowD on Fri Jul 20, 2012 9:16 am

Hello.

I have looked at the other topics (as many as I could find--there are many) regarding difficulties getting the SIM card reader to work because I can't get either of mine to work.

Two questions:

First, I see advice to re-solder the joints. I can re-solder the joints but I'm afraid that I'll burn out components. Would you recommend removing the existing solder as much as possible and starting over, or simply reheating the joints?

Second, I would like some assistance with diagnosing by using a multimeter. However, I'm not able to determine what should/should not have continuity (without power applied), what voltage level should appear on which pins of the IC (with power applied), etc. Are there any simple tests I can perform that would help to narrow things down? The schematic helps but I'm not advanced enough to easily tell what the readings should be using a multimeter.

Thanks for any help you may be able to provide.
HowD
 
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Re: SIM Reader test with a meter?

by adafruit_support_bill on Fri Jul 20, 2012 9:24 am

What problems are you seeing exactly?

If you post clear photos of the front & back of the boards we can review your assembly and make recommendations.

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Re: SIM Reader test with a meter?

by HowD on Fri Jul 20, 2012 9:41 am

Hello.

Thanks for the quick reply.

I did read the FAQ and thus I am trying to test whether this is an issue with my assembly of the components or whether it's an issue with the SIM card, etc.

I'm using MS Windows XP SP3 via a COM port.

I am receiving the error message
Traceback (most recent call last):
File "pySimReader.py", line 267, in buttonConnectReader
File "pySIMserial.pyc", line 111, in connectReader
File "pySIMserial.pyc", line 160, in openSession
TypeError: ord() expected a character, but string of length 0 found

Here are photos of my less-than-stellar assembly of the boards. This is why I want to know how to check using a meter--to determine if there are any shorts, opens, etc:

front_1.jpg
Front
front_1.jpg (725.71 KiB) Viewed 1469 times

back_1.jpg
Back
back_1.jpg (745.14 KiB) Viewed 1469 times
HowD
 
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Re: SIM Reader test with a meter?

by adafruit_support_bill on Fri Jul 20, 2012 9:56 am

The soldering looks alright. But is that a crack in D2?

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Re: SIM Reader test with a meter?

by HowD on Fri Jul 20, 2012 12:16 pm

Thanks for the reply--and the OK on my soldering...

No, that is not a crack, although it looks so in the photo. I compared that D2 to 3 other of the same type of diode, and they all look similar.

Thanks.
HowD
 
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Re: SIM Reader test with a meter?

by adafruit_support_bill on Fri Jul 20, 2012 12:49 pm

Are you connecting via serial port, or an FTDI cable?

It looks like the FTDI cable header was installed from the wrong-side of the board.

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Re: SIM Reader test with a meter?

by HowD on Fri Jul 20, 2012 1:01 pm

I'm using a serial port only. I had installed the FTDI header simply to have test points for a scope. Would it help to remove the header?
HowD
 
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Re: SIM Reader test with a meter?

by adafruit_support_bill on Fri Jul 20, 2012 1:26 pm

It should be fine as-is for COM port use. But the pins might be a bit short for good contact with an FTDI connector.

When you connect the 9v battery, is the green LED lighting up? Are you seeing 5v on the 5v pin of the FTDI header?

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Re: SIM Reader test with a meter?

by HowD on Mon Jul 23, 2012 7:22 am

Hello.

Yes, the green LED illuminates and I do see 5V on the 5V pin of the FTDI header.

Thank you again for your help.
HowD
 
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Re: SIM Reader test with a meter?

by adafruit_support_bill on Mon Jul 23, 2012 7:48 am

It can be hard to tell in a photo, but one of the solder joints on X1 looks slightly 'frosted' which can indicate a cold joint. Re-flow that (any anything else that looks rough of frosted) until it is smooth and shiny.

Also, you might try with a couple different SIM cards.

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Re: SIM Reader test with a meter?

by HowD on Tue Sep 04, 2012 10:47 am

Hello.

Sorry it took so long to reply!

I have not had much time to troubleshoot. I used the FTDI connector and a known-working SIM card and had success. Thus, I guess the soldering was OK.

I did not yet check with serial only.

Thanks again for your help.
HowD
 
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Joined: Fri Jul 20, 2012 8:54 am

Please be positive and constructive with your questions and comments.