A problem and a fix

[awsum140a]

I want to share this in the hope that it will help someone else.

I have two DNA100C's and one got knocked off an end table.  It took a hit to the screen that resulted in a black blob in the center of the screen making it impossible to read what was going on.  I have replacement color screens, so time for a replacement.

Took it apart, de-soldering the negative battery lead first, then positive battery lead and then the 510 lead.  Removed the board, cleaned up the pads and installed a new screen.  I put it back together in the reverse order, 510 lead, positive lead, negative lead.  Pressed the fire button, once, and the screen lit right up.  Reassembled the case.

Unfortunately when I went to unlock it it wouldn't unlock.  All I got was five orange dots on the bottom of the screen.  Now what?  I posted the problem on another forum and BillW50 suggested disconnecting the battery for a half hour.  I also opened a ticket with Evolv and got an response the same day.  Evolv asked about shorts from soldering, but there were none, so I de-soldered the negative lead again and let it sit overnight to be sure.  The objective being to clear any memory that might be maintained by a small capacitor.  The next morning I soldered the negative lead back on and immediately tested for unlock functionality.

Success!  My DNA100C was working again!

 

Two take aways -

1 - Black blobs on the screen can happen from random impact and are not necessarily liquid or screen problem related..

2 - Leaving the board unpowered will clear any memory, corrupted or otherwise.

 

Hope this helps someone else cure a problem like this.