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Problems Using Parts From Broker

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#70720

Problems Using Parts From Broker | 9 September, 2013

I have a 208 pin QFP that due to manufacture obsolescence I have to get them form the broker market. I've had several issues with the parts including; bent leads, leads that don't take solder very well, co-planarity problems, and DOA fallout after assembly. The assembler has to do a lot of after solder touch up which isn't MY biggest problem. The DOA problems are my biggest concern. This has been going on for the last 3 or 4 builds. The owner of the assembly house just suggested that moisture may be the problem. Of course I have no idea of how the parts have been stored so I guess I'd have to assume the worst. Anyway the owner of the assembly house said the parts could be "pop-corning" from moisture trapped in the QFP. He said they should be baked prior to use. I believe he said 100 degrees C for 48 hours. Does this sound reasonable to get the parts dry enough to possible control the DOA problem?

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#70723

Problems Using Parts From Broker | 9 September, 2013

For the proper baking durations for msd componrnts you should follow the ipc/jedec j-std-033b standard. Just google that standard and the pdf should come up. On page 16 there is a complete table showing the temps and durations.

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#70725

Problems Using Parts From Broker | 9 September, 2013

I wish I knew the MSL. The factory data sheet from 1995 does not list the specification.

The moisture problem makes perfect sense for what I'm seeing. When we replace these parts by hand (no reflow) the failure rate goes down to almost non-existent.

I'm just going to have to make an educated guess, coupled with the knowledge of my assembler, as to how long to bake.

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