AVR dragon possibly destroyed?

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Hi

I'm new around here and I own a AVR dragon that arrived a week ago, I really didn't want my first post to be about this and even after scanning through most of the thread posts with precautions on what NOT do with it, something happened that might have damaged it I'm not sure the forum post warnings covered this one.

I configured the dragon to do ISP and operated my circuit with an external power supply, however there was a short and the external power supply (which is a cheap Chinese 5v, 3.3v breadboard power supply regulator from eBay) didn't survive the abuse, it actually didn't't go open circuit and instead sourced +12v and took all the 5+ logic circuit with it destroying the Atmel 328.

My question is as a result of this the dragons level shifting logic received +12 volts and its acting strange, (its drawing 160mA) of power when I connected it again, I measured between VTG and ground on the dragon and it measures 30 ohms is this normal? Can the level shifting take up to 12v externally ? Have I destroyed my dragon ?? :cry:

Thank you in advance.

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I think you are an official dragon slayer......

I do not use a dragon, but my guess is that with the 12V on the input stages, that when they died they passed on the 12V to the rest of the circuitry of the dragon, thus killing it completely.

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Attached is an image of the regulators I used to power the device externally.

Attachment(s): 

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meslomp wrote:
I think you are an official dragon slayer......

I do not use a dragon, but my guess is that with the 12V on the input stages, that when they died they passed on the 12V to the rest of the circuitry of the dragon, thus killing it completely.

:( I have to wait and confirm AS still seems to pickup the dragon, both chips fail to read in HV mode (confirms the 12v pass to them) Crap! if this is confirm im going to be soooo upset! why didn't I just use a cheap zener diode for backup protection! foolish to trust a cheap ebay regulator.

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Quote:
Have I destroyed my dragon ??

Welcome and congratulations!

First because of buying Dragon, second because of frying it,
third because of buying ATTiny328, fourth because of bricking it,
and finally fifth only because of bricking LDO - who knows, this could have been a decent stuff.

Five fails in one go!
And you have not even touched the fuses yet.

Now what about the Dragon? Can you talk to it? Does it respond or blink at least?
h3vfw

No RSTDISBL, no fun!

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@Brutte chuckles!

I was on a good roll, I have successfully bricked the atmel328 it a few times,however, thanks to the posts here I managed to learn how to debug correctly and do HV programming (un-brick it) that didn't turn out to bad.

Dragon in terms of communication and PC works, leds lit (green and red), communication seems okay as I can unplug it and turn it on, AS as I mentioned registers the hardware, I suspect its the front end that's damaged.??

Can anyone confirm a 35.8 ohms on the dragons ISP VTG and ground???

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Between pin 2 and pin 6 = 248K

looks toasted!

Nigel

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248K ouch! thats high okay im officially upset about this. :(

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Dragon is half alive half dead am I still a slayer ?

Not sure how useful this is going to be but it seems HV programming works see attachment.

This is a long shot, who is able to help me repair the ISP front end, if the level shifting failed, I can try and trace the transistors perhaps??

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I am not sure if a schematic of the dragon has been officially released . You could do a search on that and check what parts might be damaged. on the other hand, put 5V on the supply and at least 1 IC will be getting warm really quick with those currents....
you could check the site of 'plons' and check if he ever posted a schematic so you can do the repairs.

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@meslomp

thanks for the suggestion, unfortunately its now in the trash, I can confirm that the low value resistance is as a result of a 6 pin component, hidden in front of one of the big power supply tantalum capacitors.

Oh well, back to using the PICKIT3 :(

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to bad,

1 for that you return to the dark side,
second as it might be that with replacing a couple of standard parts the dragon might be repairable ( at least I would have tried it, but then again I am a hardware guy doing firmware for 'fun' and always wanting to repair broken things.

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meslomp wrote:
( at least I would have tried it, but then again I am a hardware guy doing firmware for 'fun' and always wanting to repair broken things.

+1 8)

"I may make you feel but I can't make you think" - Jethro Tull - Thick As A Brick

"void transmigratus(void) {transmigratus();} // recursio infinitus" - larryvc

"It's much more practical to rely on the processing powers of the real debugger, i.e. the one between the keyboard and chair." - JW wek3

"When you arise in the morning think of what a privilege it is to be alive: to breathe, to think, to enjoy, to love." -  Marcus Aurelius

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Quote:
at least I would have tried it

One thing fits perfectly - all dragons end badly.

By the way, did someone make a poll in here about the life expectancy of an average dragon?

No RSTDISBL, no fun!