Howto find shorted component

[sasser]

1. Use injection current please anyone disscuss the best method and workflow

2. Just look at the board and touch everywhere and try and error - u dont know which one culprit.

3. Read schematic and judge itself which component to ground shorted and change. Its took long time

Or combination threes method? What your ecperience

[mariushm]

Re: Howto find shorted component

Get a thermal camera and see what's hotter than normal.
If you suspect a shorted component is in a specific area then ... get an air can flip it with the nozzle down and spray the area, instead of air you'll spray the cooling gas inside instead over the board and basically freeze the area (if you're not careful you could even create ice/snow on chips, such cans are quite effective).
Then, run the board (if possible from a current limited power supply) and see which component warms up much faster than others. This for example works very well for sram/dram chips, to spot one that's shorted or faulty from a bunch of them.

For resistors or capacitors, just probing with a multimeter can work.

Testing with current can work, if you have a very good multimeter, by measuring the resistance of the trace at specific points and where there resistance changes substantially you know there's a problem

There's also an issue of cracked ceramic capacitors or resistors that short only under some conditions like when board heats up after hours of use and may slightly expand. A thermal camera would be great for such cases .. you'd use a hair dryer or paint stripping gun to warm the board in a place you suspect there's such faulty components while checking with thermal camera and your eyes to see if some smoke or overheated smd component pops up.

[sasser]

Re: Howto find shorted component

Good explanation and thanks i learn new trick n tips from mariushm

[rievax_60]

Re: Howto find shorted component

I have been using a method explained here starting at post #25, https://www.badcaps.net/forum/showth...t=46808&page=2
I find shorted capacitors quickly if it is a faulty capacitor.
You need to have a multimeter with 10uv resolution for this method to work and understand the relationship between voltage, current and resistance.
Whatever you do or are told to do, do not apply more than 1 volt from an external supply.

[shortchange]

Re: Howto find shorted component

To find a short or multiple shorts.
Say the 3.3v supply has 4 ohms.
attach your ohm meter to the 3.3 volt line.
And using chilling spray or a heat gun.
The components that cause a change in the ohm meter is or are most likely at fault.

[sasser]

Re: Howto find shorted component

if use adjustable psu easy to see spike current either its high or not. the trend is if 19v shorted rail about 3.0-5.0A and if 3v shorted less then 3A current. 1.8v also less then 3A. thats i determine the problem.