Jr Case Coating... CAUTION!

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chuckphd53
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Jr Case Coating... CAUTION!

Post by chuckphd53 »

If you are planning on getting into your Jr case and making MODS , you may want to read this...

The case of the Jr is a trap for those that want to add a switch, or powersupply etc, or an add-on custom board as an upgrade or mod.

If you have a multimeter, grab it first and try this out!
Set the meter to ohms, and of course make sure your Jr is unplugged from power.
Take the top cover off so you can access the internal sides and bottom of the Jr case.
With each probe touch the inside the the case in different spots....
YES you will see the 'coating' on the inside of the case is 'conductive'!

This means if you are running any wires cables etc, that may be next to or touching the internal case sides, they can conduct to the
coating used inside each Jr case.

Why is it conductive, well, most electronic equipment should pass UL requirements and RF noise radiation, from power supplies, processor boards,
or any electronics that can radiate an RF energy.. So IBM designers coated the insides to act as a Faraday Cage to capture any stray noise.
Remember when grandma would turn on that 1950 hand mixer to make you a cake and the TV would go nuts with noise and lines
while you tried to watch your favorite Dick Tracy show.

Yes this is the 1960's technology, as todays electronic items are pretty much standard with filter supression designs that keep the RF to a minimum.

But when we want to 'play' inside the Jr case, and mount your NEW handwired design to allow your Jr to optically scan and detect paranormal
activities in your house with that Basic program you wrote, just be aware that if you lay it against the bottom of the case or mount it to the
underside of the top lid, you can short any exposed pins of your design to the case coating and thus shorting out your many hours of work.

So just be cautious and use plastic stand-offs if mounting to the inside case with extra room!

Chuck
“I never commit to memory anything that can easily be looked up in a book.” (AE)
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