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Delft, The Netherlands
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Sorry to dig up this almost ancient topic, but I realized I'm having similar problems with some arduino pros ordered back in august.

These arduino pros are embedded into some interactive objects, and work without problems for weeks. then, all of a sudden, the device shuts down and becomes completely unresponsive. even reprogramming the bootloader with an isp programmer does not revive the chip. I've lost 3 boards so far.

I can't find problems in my wiring, so the only things im thinking of right now are:

- brownout when shutting down (can this demolish the chip?)
- overheating atmega (through overheating the regulator?)
- overcurrent on i/o pins, they are not protected by a resistor

so, i'm wondering whether any of you recognise these symptoms. I can replace the faulty devices, but the problem seems to be coming back. So, when does the device actually fail from overheating? (That is, in your experience, i know the datasheet specs)
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London, England
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Mark,

Does your app happen to be putting stuff into the EEPROM on the chip? Most people forget that EEPROM can only support so many rewrites. Might be totally unrelated. But worth a look.

Cynar
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Delft, The Netherlands
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Nope, EEPROM is not used in this application. But if it was used, would that mean the chip becomes totally unresponsive to anything?
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Quote
So, when does the device actually fail from overheating?

When the silicon temperature exceeds the maximum. This is not case temperature.

In general for every 10C rise in temperature the expected life time of a semiconductor device half's.

- brownout when shutting down (can this demolish the chip?) NO

- overcurrent on i/o pins, they are not protected by a resistor Only if the design is wrong and then I would expect to see just the output pin go not the whole chip. I expect the chip is dead as it won't re program.

- overheating atmega (through overheating the regulator?) one does not follow the other, an overheating regulator should just shut down. It can overheat the whole box but that depends on how the box is physically constructed. Do you have any air movement over the electronics?
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Turku
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If you have two boards, like you seem to have. You can check your cpu, if you take a cpu from a dead board and put it into a working board. If your regulator is bad, your new board will work with the old cpu.

At least on my Duemilanove board have a socket under the cpu.
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.. not the pros... They are SMT
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