what causes the 30f131 component failure?

[budwich]

I have been reading a bit around the sc card faults and the resulting issues with the 30f131 igbt. I haven't really come across much discussion about the component failure other than the "catastrophic discussion" around fakes. But my query is more towards the original component and the results which see a number in "short condition" failure. Is this caused by "over current" or "over voltage" situations, heating or something else. Is there always a "subtending" reason for the failure or can the failure of the original component be a "sole cause" (poor component: quality / design / assembly)?

Anyways, just curious for understanding or lack thereof.

[tvtimmy]

Re: what causes the 30f131 component failure?

The screws that mount the boards in the tv come loose causing the boards to lose their grounding points. Thats it. New screws have lockwashers on them. 2011 and 2012 Panasonic plasmas have this problem. The heating and cooling plus the vibrations from the transformers turn them loose and the you hear a BANG! Tv is down untill its repaired and new style screws are used.

[budwich]

Re: what causes the 30f131 component failure?

But... there does appear appear to be any physical damage to the factory originals. They are just shorted. For lots of "stuff", if you lose a ground, that doesn't usually cause a component failure, operation failure (intermittent or otherwise), but loss of ground would mean reduced current. I understand that there may be issues with the grounding points but don't see how that causes the failure of the component. And if so, why doesn't it take others components (ie. capicitors, ic, resistor, etc) with them. Is it a "cascade type failure"... one 30f131 fails and others take up the load and ultimately all fail at which point the set "dies"?

[martino]

Re: what causes the 30f131 component failure?

If you would lose ground completely nothing would blow up,it would just stop working. Problem here is that it only partly loses ground,hence drawing a lot more amps.The 30f131 are the hard working guys on that board and the first to get effected by this increase in amperage and it quickly goes higher then their rated value with a total internal meltdown as a result.
One will die first,and they work in parallel so it's partner will try to do one more cycle but get's dead shorted by the first guy.

[budwich]

Re: what causes the 30f131 component failure?

OK... I can understand that kind of fail mode. I guess another question would be outside of the "mechanical fixes" that take into account the "bolting", is there other techniques such as providing alternative ground paths to key points using wiring or strapping to help ensure better grounding?

[martino]

Re: what causes the 30f131 component failure?

You could but if you clean up all screw contacts on the board(both sides) and use proper screws then it will never happen again.