SMD caps - any way of telling which is ground?

[JonathanAnon]

Hi guys,

This is pretty basic, but I've no schema for a particular board and I need to know which side of an SMD capacitor is ground. There are no ICs near by and there is a short to ground in some section of the board (so both sides of the caps are 0 ohms to ground).

Any ideas?

[digitalpc]

i use power supply setup the voltage about 3volt 0.8amper in both side and see which side
drop more voltage is your ground, example one side of smd is 0.2v 0.8amper(this is your gorund) another side is 1.8v 0.8amper(this is your plus)

hope u understand what i mean

[JonathanAnon]

Originally Posted by digitalpc

i use power supply setup the voltage about 3volt 0.8amper in both side and see which side. drop more voltage is your ground, example one side of smd is 0.2v 0.8amper(this is your gorund) another side is 1.8v 0.8amper(this is your plus)

hope u understand what i mean

yeah I was going to just do that. I guess the level of voltage drop is dependent on the type of short also. if it's a complete short then I guess there will be no significant in the difference of the voltage drops on both sides of the cap.

I think I may just inject both sides at this stage and see what happens.

[stj]

what type of cap, electrolytic, tantalum?

[JonathanAnon]

SMDs, thought I was sorted when I had another board that was similar, but as it turns out it is different.

I'm just injecting 4 amps in to both sides and nothing is warming up. I scaled it up from 1 amp in 0.5 amp steps.

[budm]

Might get more reply if you upload good clear pictures of what you are dealing with.