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Posted by: DaveB Mar 5 2022, 08:05 PM

I'm removing the tar off the relay board. I'm finding areas which look like a soldering iron touched and melted the plastic. I don't know if this was used to tack down some of the traces or something else. One area looks like someone laid down a soldering tip.

Was this normal or something else?

Thanks,

DaveB

Posted by: Superhawk996 Mar 6 2022, 04:50 AM

Normal

It is heat staking used to hold the traces in place during assembly.

Both boards I’ve cleaned had same heat staking in places on the board.

If you look carefully you’ll see they melted top down toward the trace. If the trace had overheated they would be melted at the base where the trace sits.

Posted by: 914Sixer Mar 6 2022, 07:43 AM

Yes they are all that way.

Posted by: DaveB Mar 6 2022, 02:55 PM

Great - Thanks for the help.

After I check out and repair the board, I was going to use a clear epoxy instead of the tar to seal the traces. My other option is to use an RTV with a vacuum. Anyone have issues using an epoxy for the environmental seal?

Thanks,

DaveB

Posted by: GeorgeKopf Mar 6 2022, 08:07 PM

I posted this question about three different types of relay boards.

http://www.914world.com/bbs2/index.php?showtopic=355156&hl=

George

Posted by: DaveB Mar 6 2022, 09:43 PM

QUOTE(GeorgeKopf @ Mar 6 2022, 06:07 PM)

I posted this question about three different types of relay boards.

http://www.914world.com/bbs2/index.php?showtopic=355156&hl=

George

George,

Thanks for the link. I didn't expect to see so much variability in these relay boards.

DaveB

Posted by: Van B Mar 29 2022, 06:23 PM

I took my relay board off to clean it and discovered the underside was cracked like the Nevada salt flats.
So, I ordered some of this stuff to give it a good reseal:
https://www.amazon.com/MG-Chemicals-Black-Retardant-Compound/dp/B07B3Z8CLY

Posted by: robkammer Mar 30 2022, 08:48 AM

QUOTE(Van B @ Mar 29 2022, 08:23 PM)

I took my relay board off to clean it and discovered the underside was cracked like the Nevada salt flats.
So, I ordered some of this stuff to give it a good reseal:
https://www.amazon.com/MG-Chemicals-Black-Retardant-Compound/dp/B07B3Z8CLY

I took the easy route and bought a refurbed board from BDStone, pretty sure he uses black Flexseal and it's really nice.

Posted by: Van B Mar 30 2022, 09:51 AM

I considered that, but mine cleaned up really nice and I like the idea of using modern flame retardant circuit board epoxy (potting compound). This stuff will probably outlive me given the service temp is -40F to 347F. The engine bay heat won't even come close to pushing it's performance envelope.

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914World.com _ 914World Garage _ Did original relay boards have plastic melted near traces?