PCB Layer to layer short on a low voltage power plane - how to find it?

[Prott]

Hello!
Recently I have a problem finding a dead short (as far as my cheap multimeter is concerned) on a multilayered (12 layer) PCB. It is caused due to mechanical stress (warping the board and, I assume, cracking inner layers). Injecting voltage of 0.9 V (operational voltage of that part of the circuit) and drawing 0.5 W doesn't cause any visible hotspot on a thermal camera.

Does anybody have any tips & tricks in order to locate the short more or less precisely? The area has a lot of powerplanes, so it's both blessing and a curse.

Silly idea no. 1: Can I increase the voltage above the operational voltage in order to draw more amps and... hope the short won't burn through before I find it?

Thanks!

[huaji62]

A short found after raising the voltage will not burn through the printed circuit board, but it should not exceed the maximum voltage withstand of the chip. Sometimes the short location will be around a via hole and you can drill some through holes to fix the short, but I've only encountered two motherboards like this.

[CapLeaker]

Look up something like an Leakseeker 89 or similar.

[sam_sam_sam]

Look up something like an Leakseeker 89 or similar.

Thank for sharing this information these testing equipment

[CapLeaker]

Thank for sharing this information these testing equipment

No problem. All you need is something that can read very small resistance values. That is something a DMM cannot do.

[sam_sam_sam]

No problem. All you need is something that can read very small resistance values. That is something a DMM cannot do.

I am seriously considering buying one because there are times I could have used one I have used my Blue ESR tester to figure out if the device is shorted or not this not the best way to do this but you use what you have on hand

[CapLeaker]

I've got the Leakseeker 89. I don't use it a lot, but if I need it it's another gods send.

[Prott]

Thank you CapLeaker! The leakseeker looks like an amazing piece of equipment to have. I think I might buy the bare pcb and put it together as a project. Hopefully it will not have a short circuit in the pcb

[harp]

Recently I have a problem finding a dead short (as far as my cheap multimeter is concerned) on a multilayered (12 layer) PCB. It is caused due to mechanical stress (warping the board and, I assume, cracking inner layers). Injecting voltage of 0.9 V (operational voltage of that part of the circuit) and drawing 0.5 W doesn't cause any visible hotspot on a thermal camera.

Dead short or 0.5W ?
How you get 0.5W, it may be visable in specific condition, what is voltage drop and current consumption, have you try evenly cooling pcb in fridge, and monitor in it, just apply power for long time and see what you get? Half of watt have power to maintain different temperature, if not spread on large area.

[sam_sam_sam]

Look up something like an Leakseeker 89 or similar.

Did you buy this as a kit or did you buy as assembled unit

I found this as a kit is this price reasonable for it being a full kit including the enclosure and all the parts including the micro controller programmed

https://www.ebay.com/itm/283992280583

[sam_sam_sam]

Thank you CapLeaker! The leakseeker looks like an amazing piece of equipment to have. I think I might buy the bare pcb and put it together as a project. Hopefully it will not have a short circuit in the pcb

Just make sure that you can get the micro controller program so you can program it yourself

[CapLeaker]

Did you buy this as a kit or did you buy as assembled unit

I found this as a kit is this price reasonable for it being a full kit including the enclosure and all the parts including the micro controller programmed

https://www.ebay.com/itm/283992280583

I bought it assembled 12-14 years ago.