Author Topic: Need help to find 4 layer short  (Read 383 times)

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Offline Radiosonde

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Need help to find 4 layer short
« on: August 07, 2019, 11:27:12 am »
Hello
After I received my first 4 layer PCB from JLC I realised that I have a short between GND and PWR (5V) Layer...my stackup is:

Signal (RF)
GND
PWR (5V)
Signal

I allready tried to drill out vias, but I didnt show any effect, I am also running 5A trough the board since 10min, also no effect.

It would be nice if someone could take a quick look at my gerbers.

Best Regards
 

Offline ludzinc

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Re: Need help to find 4 layer short
« Reply #1 on: August 07, 2019, 11:36:07 am »
Tried running a DRC on your design?
 

Offline Radiosonde

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Re: Need help to find 4 layer short
« Reply #2 on: August 07, 2019, 11:39:52 am »
Hi
Yes, indeed, on both schematic and pcb
But it doesnt show anytrhing usefull, only stuff like, to near where there is clearly enough space.

Regards
 

Offline NANDBlog

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Re: Need help to find 4 layer short
« Reply #3 on: August 07, 2019, 11:56:20 am »
You have some weird artefacts on your GND plane.
Looks like your inner annular rings have some things going on. Look at those ones which are between the SMA connector, little bit to the left.
 

Offline Radiosonde

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Re: Need help to find 4 layer short
« Reply #4 on: August 07, 2019, 01:01:27 pm »
Ok, because the 5V plane is only connected with 39 pins i cut all the traces from the plane (vias) to the ICs, the short is still here, so what does this mean?
There must be a short directly between planes?

Regards
 

Offline nctnico

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Re: Need help to find 4 layer short
« Reply #5 on: August 08, 2019, 12:35:07 pm »
Hi
Yes, indeed, on both schematic and pcb
But it doesnt show anytrhing usefull, only stuff like, to near where there is clearly enough space.
If there are DRC errors then you have to solve these. Sending a board out which has DRC errors is asking from problems. Did you check the Gerbers using a gerber viewer?

You may be able to find the short using a thermal camera or multimeter (measuring the voltage between gnd and 5V) while running current through the board but it might be hard when solid planes are involved.
« Last Edit: August 08, 2019, 12:42:42 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 


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