[Techtoolslist] Using Flir android thermal camera to track down short

[davids at oz.net]

So I have an MCR board set which roasted the inductor on the +12v rail.

 

Swapped the inductor for a fuse holder temporarily, instantly popped a .5A fuse, and then a 1A fuse.

 

Pulled the sound board off the set (only thing that actually uses the +12).  Hooked it up to my bench supply which can do constant current or constant voltage.  Set it the voltage at 12 and dialed the current down to 0.

 

Started turning up the current while watching the board with my phone using a FLIR One Pro camera attachment.  The voltage stayed < 1v as the CC was kicking in.

 

At .5A I could start to see the +12v and Analog ground traces light up. And one cap in particular was showing.  Brought it up to 1A and that cap was definitely glowing.  But not even warm to the touch.  CP20 a 10MF 25V Axial Tantalum cap.

 

Turned off the power supply and cut the cap leg.

 

Turned on power supply and current was negligible and voltage was at 12V.

 

Total time to find it, 15 minutes and most of that was setup.  

 

I had tried using the HP current tracer on this board but wasn’t getting very good feedback and after an hour or so I gave up with it.

 

This camera is kind of expensive ($300 on amazon).  And I was skeptical about how effective it would be.  I was AMAZED at how well it was showing the current path through the traces at even a low current level.   And you can use the software to take pictures & video of the work for later review.

 

I had borrowed this unit from someone at work and was talking to the wife (aka the finance committee) about this and showed her the pictures.  Then mentioned there was a $200 non pro unit and a $300 pro unit (which I was using).  She said “Spend the extra $100, it’s a tool not a toy”.  I knew I married the right woman 😊

 

David