Popcorn damage

Can someone who has seen it say please if it is obvious from the package where this has occoured ?

Ive been having problems with toaster oven tecnique . Decided to have some professionaly done to see whats going on.

come again?

I use a toaster oven for reflow soldering with a controller. Pcb pool sell them. Recently had problems with a known good design failing. I use a esd protected workstation with components from the usual scources.

Random failures arter soldering makes me wonder if popcorn damage may be the cause. Not sure if it is obvious to the eye though as i have not seen it.

Thanks that makes more sense.

Not sure if it is obvious to the eye

No it is not always. It is caused by moisture in the leads of a surface mount device expanding rapidly and putting a mechanical strain on the lead body interface. This can crack internal wiring but when the pressure is relieved it snaps back so normally it is not visible.

You need to test the components out of circuit, an open circuit signal lead will indicate damage like this.

Thanks, its difficult to test for this. Most of my devices are fets. Looks as though i may have to bin my inventory and start again.

its difficult to test for this.

Why? Just remove the FET and use a multimeter.

Sot23 Big thumbs. Difficult to find as well once removed.p :(

Slow baking is required to dehydrate packages to eliminate the possibility of this
happening, this is why you’ll find a lot of ICs supplied in hermetic packaging
with a moisture indicator card. Personally I’ve not seen this happen, but am
aware of the risk. I believe only epoxy packages are affected, ceramic are immune.

The problem is more serious with large boards as a single failure can cause loss
of a whole expensive board.

Turns out im barking up the wrong tree. Pack of new 60 V fets breaking down at about 32 V.

Hmm, eBay specials?