Re: External Power #starparty #EXOS2 #TECHNICAL

Skull HQX

Thanks Jerry,

It's good to know it has reverse polarity protection. But I'm not going to test it!

Last year I blew up a €400 synthesizer because I mistakenly plugged in a feed that actually was 9V center-pin negative. Most guitar fx pedals use 9V center-pin negative and the plug is the same 2.1x5.5mm one a lot electronic music instruments use. Those guitar fx pedals are used with synthesizers btw. I can't play guitar and it even can be argued I can't play keys! But I digress.

Strangely my most expensive guitar fx pedal, an Eventide H9 Max, is center-pin positive with a 2.5x5.5mm barrel, but it fits the 2.1x5.5mm plug... So what could possibly go wrong. Yeah, I also managed to blow up that one some time after that first mistake. No working reverse-polarity protection on that thing either! And that is a €700 device. I was mad at myself (something like that never happened to me before in my life) but after ordering a 25ct SMD part I could easily repair it. The synthesizer though... I could bring it back to life (took an ever cheaper part) and even get it to boot, but part of the processor that holds the programming was dead and couldn't hold a reflash. I gave up repairing it.

Since then I have color coded all plugs and leads. And never again will assume a device has a robust reverse-polarity protection! :-)

Clear skies!

On Sat, Feb 8, 2020 at 5:37 PM Jerry Hubbell - Explore Scientific VP Engineering <jrh@...> wrote:
On Sat, Feb 8, 2020 at 06:20 AM, Skull HQX wrote:
I’m not sure if the mount has a robust reverse polarity protection but you don’t want to find out the hard way!
Yes, the mount controller has reverse polarity protection on the 12 Vdc input power. The connector is 2.1 x 5.5 mm with the pin at 12 Vdc.

Jerry Hubbell
Vice President of Engineering

Explore Scientific, LLC.
jrh at
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