Extron Crosspoint SHOCKING ME!

[Dochartaigh]

I have an Extron Crosspoint Ultra 128HVA matrix switcher with ADSP. It's rack mounted. When I helped myself off the ground by putting my palm on the corner of the rack I sometimes noticed a really weak tingle - honestly thought it was me pinching a nerve in my hand for the longest time... but this past weekend I rewired everything with new BNC cables, and the metal of the composite RCA port on my PS1 RGB SCART cable (used for plugging in a light gun) touched my leg, and yeah, I got a slight shock. Did the tongue test as well to triple check (don't tell me you never tried that at least once with a 9v as a kid lol), and it's definitely a very low level shock.

I talked to a friend who's recapped multiple Extron's before and he's surprised - there's not much inside the Extron to short out to the case, then to the rack, and/or to the wires plugged into the INPUT side of it... These Extron's with ADSP output "5v p-p"? TTL sync, right? Could that 5 volts be enough for this very low level shock? It would be weird that it's coming from the input side though (of the cable that's plugged into the back of a PS1 or PS2).

Any advice on what to do? Could this somehow (weirdly) be quasi-normal? Should I trash this $130 piece of hardware and buy a new one to be safe? Not a single issue on any system or multiple monitors I've had setup...

I'm also wondering if one of my systems could have a short in the SCART cable? I know the sync stripper chips built inside some SCART heads use 5v? off the console to power them, so that could technically shock you? I was about to unplug everything and test them one by one...but most of these plugs have covered pins so it's not like I can try to shock myself that easily to narrow down the culprit...I forget if I noticed a slight shock from the output side - those do have bare metal and I can double check those. I also have a multimeter...but I've honestly never used it in my life so if you want me to test something please let me know how!

[Syntax]

There's an earth leak in your house, you can check how many volts with a multimeter.

If you plug something else in that has an earthed steel body like a computer case and wet the palm of your hand you should still feel it. (edge of the bicep is nice and sensitive too lol)

You can cut the earth to it and it will stop, but then its not really safe to touch if it ever decided to fail internally.
I've had to do this for sound a system that was picking up interference from earth leaks and other equipment in my house.

[parodius]

you can check how many volts with a multimeter.

You mean, earth vs neutral ?

[gojira54]

Casing to known good earth

[Dochartaigh]

So any electricians here? I did some research on earth leaks and now remember how my metal-cased PC for the longest time was shocking me as well (more than what I would consider a regular static electricity shock to be - it made the HDMI image on my TV turn black for a sec when it happened) - hasn't happened for a while though.

My house is from the late 1950's. When I moved in ~5 years ago I had brand new electrical service straight from the pole installed, brand new 200 amp Siemens electrical box, brand new ground (rebar? pipe?) pounded into the ground a couple feet. In those 5 years I think I've had one single breaker pop, once, ...so things seem pretty solid electrical-wise.

I know the original outlets in the house were 2 prong, I believe non-polarized, and I thought they house witing didn't have had the 3rd ground wire - I will pull an outlet and double check that. My uncle, who installed all new modern 3-prong outlets as a housewarming present (who I think had an electrician background like 40 years ago) is pretty sure everything was properly grounded, since if those outlets weren't gorunded he would have had to do other steps to properly install those 3-prong outlets – and he doesn't remember having to do that.

He suggested I grab that multimeter (which I've never used before and see what reading I get off the server rack (also saw some videos on testing the amount of earth leakage my outlets have). When I mentioned I tried to shock myself last night and couldn't, and mentioned how I rewired everything on the Extron over the weekend, he said one of the older devices (a la 1986 NES or 1989 Sega Genesis come to mind...) plugged in via an unpolarized plug could very well have something wrong with it, and switching the polarity of the plug (by accident, while I rewired everything and plugged it back into the power strip), could have fixed this problem and is why I'm not getting shocked now. ...which means I should maybe do a 1-by-1 test of each and every device and see if if that can narrow it down...come to think of it, I did have to order a new NES (original) power supply because the old one died...coincidence? (or maybe I'm just grasping at straws now).

Does the above sound like a good plan? Anything else you guys would recommend?

[andy251203]

You may have already inadvertently mentioned this in your post above, but there's a chance the hot and neutral wires may have been reversed on some of your outlets.

[Dochartaigh]

You may have already inadvertently mentioned this in your post above, but there's a chance the hot and neutral wires may have been reversed on some of your outlets.

I'll run this test with my multimeter:

https://www.youtube.com/watch?v=ELiTfD6ehuI

^^ that's just showing how my multimeter should read 0 volts from Neutral to Ground, and ~120 volts from Hot to Ground, correct? (and if it's reversed then I know they're switched and will re-wire that outlet - and test the others!).

Anything else I should check for (again, I'm literally googling how to use my multimeter as I've never used it before). I will also run the above test to an outlet on my power strip to make sure that strip is wired correctly as well.

How about the plugs off my consoles? I'm pretty sure most of them don't have a thinner and a wider prong, so those are called non-polarized plugs, correct? Would the direction I plug those into the power strip matter at all?

[Syntax]

Ive got about 12v leak in my house, if I reach around the pc and my arm touches it I get a zap.

A lot of my equipment is connected to power via a Furman and ill probably just make a new earth stake and wire to that as I cant find the fault in the house.

Shits me when I plug in a powered harddrive and watch the usb shielding spark and my screen flicker.. cant be good.

[Dochartaigh]

So I tested several outlets in that room (and a couple others around the house), all read around 117-120 volts from ground to hot. From ground to neutral most are right around 0.0 volts (some fluctuation but with enough wiggling of the probe I could always make good ground and it was under a volt or two if not right around 0-0..

I also can't shock myself for the life of me anymore. I'm kinda leaning towards that bad Nintendo power supply possibly doing this? It was able to power the NES during the time period when I was getting shocked last, then a couple days later it wouldn't turn the NES on at all so something definitely fried in it...that's all I can think of...