Probably dead xbee adapter board

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uttaco
 
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Probably dead xbee adapter board

Post by uttaco »

So I made the stupid mistake of putting a bunch of components and batteries into a box, long story short I burned out my xbee radio. I want to know if there is a way I can test the xbee adapter board to see if it is still good. I'm pretty sure the voltage regulator is bad, when I plug the board into power the regulator instantly gets hot, but I don't know what other components to check or if its even worth it to check them.

I would prefer not to have to buy a new radio and board but I don't want to burn out any more radios, they aren't cheap.

If you want or need more information just let me know.

The voltage that burned it up was probably 18V (speculation). From what I remember from the data sheet the regulator is rated to 6V I think.

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adafruit_support_bill
 
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Re: Probably dead xbee adapter board

Post by adafruit_support_bill »

Depending on how the battery voltage entered the circuit, the most likely victims would be the regulator and the 74AHC125N buffer chip. Both reasonably inexpensive parts. It is possible to have fried the LEDs also. But the board should work without them. The electrolytic caps for these kits are usually 10v rated. But unless it is bulging (or already popped) it is probably OK.

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zcapozzi
 
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Re: Probably dead xbee adapter board

Post by zcapozzi »

This sounds similar to my silly mistake. I plugged the FTDI leads into the XBee adapter backwards and got a surge. Now, even with the right leads connected the right way, I'm not getting a response from the XBee.

Is there a way to test whether the regulator or the buffer chip are the victims? And to confirm, is the radio itself ok at this point? I was a bit unclear from the previous post which pieces would need to be replaced. From what I read, it sounds like:

1. Adapter board is ok
2. Regulator or buffer chip need to be replaced
3. Radio is ok, just needs to have the adapter fixed

Do I have that right?

- Zack

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adafruit_support_bill
 
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Re: Probably dead xbee adapter board

Post by adafruit_support_bill »

The OP had already concluded that the radio module was dead and was trying to determine if the adapter was salvageable.

If you connect the board to 5v and you get 3.3v on the 3.3v pin and the regulator doesn't start to overheat, then the regulator is OK. If you put 5v on the adapter's Rx pin and get 3.3v on the XBee module Rx pin, then the buffer is working.

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zcapozzi
 
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Re: Probably dead xbee adapter board

Post by zcapozzi »

Yikes, just ran your test. Regulator got super hot. Guess that's the issue then. To confirm, I ran three tests since I have a working xbee and adapter.

If I use the working adapter and the suspect xbee, the regulator on the working adapter gets super hot. Not good.
If I use the suspect adapter and the working xbee, the regulator on the suspect adapter gets super hot. Not good.
If I use the working adapter and the working xbee, the regulator doesn't get hot and the xbee gets picked up by XCTU.

Seems like both the regulator and the xbee itself are fried.

Thanks for the help.

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zcapozzi
 
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Re: Probably dead xbee adapter board

Post by zcapozzi »

Aside from my "test it with a board I know works" approach, is there a test I can do to the radio module itself similar to what you suggested for the board itself.

You said: "If you connect the board to 5v and you get 3.3v on the 3.3v pin and the regulator doesn't start to overheat, then the regulator is OK. If you put 5v on the adapter's Rx pin and get 3.3v on the XBee module Rx pin, then the buffer is working."

Is there something similar that I can do with the radio module itself to test whether it is a lost cause?

Thanks again for all your help.

- Zack

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adafruit_support_bill
 
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Re: Probably dead xbee adapter board

Post by adafruit_support_bill »

The real experts on the internals of these modules are the folks that make them at Digi. They may be able to suggest some simple diagnostics you can run on the module:

http://www.digi.com/support/forum/

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zcapozzi
 
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Re: Probably dead xbee adapter board

Post by zcapozzi »

Good point. Thanks again for the help.

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