Dear Technetters!

We sometimes receive failed boards from the field with failures on BGA's for  repair.
Supposing there is no problem with the BGA as a component, supposing that the X-ray test (feinfocus tiger) does not reveal any problems in the solder joints (with exception to cracks which are very hard to detect), what procedure would you suggest?
We are concerned with the following:
Reliability
Cost: the assemblies are still our responsability
We are considering:
Scrap
Repair by reflow and electrical test
Repair by installing a new component and electrical test- this includes the possibility of visual inspection of the area under the failed component and finding more out about the failure mechanism)
Lately we have performed several destructive tests in order to  see the nature of the failures which could not be repaired by reflow, and found:
through hole cracks or corrosion in plugged holes
pad lifting and conductor cracks
solder joint cracks
All these were not detected by X-ray.
Could you suggest the best procedure?

Gaby

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