Archive for July 21st, 2010

PTT Switch Contact Corrosion

Posted by Ed in Amateur Radio, Electronics Workbench, Recumbent Bicycling on 2010-07-21

Corroded Pushbutton Switch Contacts

Corroded Pushbutton Switch Contacts

The PTT switch for the amateur radio on my bike got erratic: pushing the button didn’t seem to be producing reliable RF. I’d have sworn when I bought the switches that they were washable-during-PCB-assembly: at least moderately sealed.

Wrong.

Turns out there’s only the seal you get from snug-fitting mechanical parts. I carved off the square aluminum bezel and found an ordinary dome switch underneath, with contacts that actually looked better than you’d expect after half a decade on a bike. But, yes, I could see why it was erratic.

Lacking anything smarter, I installed another one, just like the other one, with a square of Kapton tape over the button. Not a great seal, but maybe it’ll be Good Enough.

Here’s what the button looked like in happier times…

PTT Button

PTT Button

Memo to Self: Tape up the other PTT buttons?

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