Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Short circuit tracer/finder ?

Views: 299

#84392

Short circuit tracer/finder ? | 10 February, 2020

Hello,

Would you please recommend a proven Short circuit tracer/finder ? From time to time, to fix defective boards, I need to find a source of bridge between Power and Ground. I had used a simple Shortsniffe, but it was very hard to trace the origin of the bridge between Power and Ground.

Please advise if you have a good experience with certain equipment.

Regards, John

reply »


Jer

#84476

Short circuit tracer/finder ? | 18 February, 2020

I have used infrared imaging to find electrical shorts on logic boards between the 5 Volt buss and ground. You can power the electrical short up to draw 50 to 100 mA and then look for the warm spot in the infrared display.

reply »

#84481

Short circuit tracer/finder ? | 19 February, 2020

Thank you for your advice Jer.

BTW, may I ask the model name which you have used ? I'd like to buy and try it. Does it work well for the bridge underneath of components ?

Regards, John

reply »


Jer

#84488

Short circuit tracer/finder ? | 19 February, 2020

Hi John,

We had a FLIR system with interchangeable lenses and good thermal resolution for the time (15 years ago). I see the new ones now at a fraction of the cost which we paid and they have better resolution. Amazing how the infrared imaging technology has progressed. Most suppliers will gladly demo a unit for you which is what I would recommend in your instance.

Bridges under components may take a bit longer to realize where the localized heating is taking place. You can image both sides of the assembly looking for the hot spot which helps if large components are obscuring the direct view of where the short is. This will also ID a component which is electrically shorted from ground to the voltage rail as well.

Place the PCBA and camera in a good steady holding position. Power up the short with current limit of around 10 mA to start with and look for the first area to indicate increased localized heat. You then reposition or zoom in to get finer details. Generally, you can increase current substantially if needed, however too much current could "fuse open" your electrical short which would then be impossible to find the electrical culprit and the assembly would not be reliable.

reply »

#84490

Short circuit tracer/finder ? | 19 February, 2020

Thank you again Jer !

reply »

Manufacturing Software

PCB separators