Fix for broken JTAGICE3

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midea31
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Joined: Fri. Jul 22, 2011
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#1
Posted by midea31: Thu. Jun 13, 2013 - 03:14 AM
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Hi All,

Recently, I was having troubles with my ice3. At first it was just some intermittent cases of not seeing the target voltage or not reading the signature. But then it worsened to not being able to see any target voltage at all. I know it was not by board because I could use my dragon on it just fine. Then I noticed that my board's power becomes 0V everytime I connected the ice3.

So I investigated a bit and found that the protection diode across Vtg and Gnd is busted. This was why my board's power lines were shorted.

So I replaced the diode and voila! it's alive!
I do not know the part number of the original diode but I replaced it with 1SS181.

Below is a picture the ice3 with the replaced diode.

Attachment(s): 

Image icon jtagice3.png

Tags:

AVR Microcontrollers, megaAVR and tinyAVR
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samgao001
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Joined: Thu. Feb 28, 2013
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Posted by samgao001: Wed. Oct 29, 2014 - 01:14 PM
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I know this is an old thread, but for future reference.

 

The correct part should be GSOT05C by Vishay.

 

Check out this datasheet and look for GSOT05C : http://www.vishay.com/docs/85824...

Last Edited: Wed. Oct 29, 2014 - 01:16 PM
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Patratacus
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Posted by Patratacus: Thu. Jun 1, 2017 - 09:32 PM (Reply to #2)
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Thank you for posting this.  I just found this 3 years later from when you originally posted it.  I'm trying to figure out why I can't just not have the protection diode at all if it's broken.  I thought all it's doing is for ESD suppression so it should be transparent when there isn't any ESD event.  Therefore, why can't I just remove it and have the unit working?  I think I have the same problem and I don't have the correct diode on hand.  I just removed the part and tried to read a device.  I kept getting a 0V so it means that I would need the replacement diodes.

 

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