Author Topic: smoked PCB  (Read 1966 times)

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Offline vidamTopic starter

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smoked PCB
« on: June 16, 2008, 08:29:40 AM »
Hi,

Saw smoke rise from my atmega168 based PCB board. Now I cannot connect to the ATmega168 in ISP mode. I looked at the circuit board under a high magnitude microscope but did not see any evidence of where the smoke originated. There was no obvious places where the smoke originated on the atmega 168 or the surrounding components. Also the voltage regulators still work.

Should there not be  whole in one of the chips where the smoke came from? Also the led status light no longer light up and those were turned on by the atmega 168 interrupt pin.

Offline izua

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Re: smoked PCB
« Reply #1 on: June 16, 2008, 08:53:23 AM »
can you show us a high-res pic?
maybe it was a cap, the small tantalum smd type.
what were you doing when you let the smoke out?
Check out my homepage for in depth tutorials on microcontrollers and electronics.

Offline vidamTopic starter

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Re: smoked PCB
« Reply #2 on: June 16, 2008, 10:18:51 AM »
I was trying to do High Voltage Programming to do a chip erase, and clear the lockbits because I had this theory that my programmer could not enter Programming mode successfully because I sent the DWEN fuse and the lockbits at the same time. I don't think this actually happened but it is my only theory that seems to make sense as to why my ISP could not enter programming mode. So in HVP I was applying 12 Volts to RESET when I saw smoke for high programming voltage. I can't post a high res schematic. sorry

[edit]

There are lots of the small tantalum smd type capacitors on the board.

[/edit]
« Last Edit: June 16, 2008, 10:21:10 AM by vidam »

Offline ceruleanplains

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Re: smoked PCB
« Reply #3 on: June 17, 2008, 10:11:58 AM »
you can send me the pic in an email and i can post it to my website for you if you want to get some help.

Offline vidamTopic starter

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Re: smoked PCB
« Reply #4 on: June 17, 2008, 10:16:08 AM »
you can send me the pic in an email and i can post it to my website for you if you want to get some help.

I use photobucket to display my images in the posts.

Thanks anyway.

Offline vidamTopic starter

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Re: smoked PCB
« Reply #5 on: June 17, 2008, 12:06:46 PM »
Replaced the ATmega168 and downloaded my program. It works again, seemingly. Now to check the rest of the functionality.

Offline Admin

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Re: smoked PCB
« Reply #6 on: June 19, 2008, 06:46:23 AM »
I once had a circuit release a lot of smoke . . . but I couldn't find anything wrong with it, no burnt parts or anything . . . and it worked again when I turned it back on . . .

 


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