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Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

Relay failures

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Relay failures | 29 July, 2014

We have been struggling for a while with some through hole sealed mechanical relays that fail at test after they have been sitting a while. They will initially pass test, but seem to fail if they sit for a few days. We made sure our wave process was well below the datasheet specs so they are not over heated and they are sealed and approved for a our wash process. Any one ever experience this or have any ideas? Thanks!

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Relay failures | 30 July, 2014

I have seen similar issues in the past.

1. We had an issue when the relays were installed a leg was bent over. This cracked the epoxy base and allowed water and flux to get in.

2. We have had to bake relays after washing. We would cut open the vent hole on the top and bake at 100c for 12 to 24 hours.

Hope some of this helps.

3. Also we have had to add power to the relay legs and cycle the relay.

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Relay failures | 31 July, 2014

If it has been determined that it is definitely the relays (and not some other circuit device), you'll want to get the vendor/manufacturer involved for some failure analysis. They'll cut open the components, and try to figure out what's going on in there.

We had it happen a couple of lifetimes ago. Failure analysis revealed dendritic growth inside the sealed component. The seal wasn't breaking down in process, and we weren't introducing moisture into the appeared as though the condensation was remaining in there after component manufacturing, and being exacerbated by our process (wave solder and wash).

This may not be your issue, but, if you're having component level failures, I'd definitely get the manufacturer involved in helping to determine the root cause.

Cheers, ..rob

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Relay failures | 31 July, 2014

Turns out the seal was being broken from poor handling allowing moisture in. Thanks for all the info pointing me in the right direction!!

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