Any electricians on the forum? Or: why am I being shocked by a SCART cable

[danstan21]

Today I was rearranging my retro rig, and I noticed two things:

#1 When I turn on my Gamecube, the power LED on my Super Famicom (dimly) lights up. This happens even when disconnecting the SFC from the mains, so the power must be coming through the RGB cable.

#2 The RetroGamingCables SCART sync-on-luma cable on my RGB-modded N64 is live, even when the console is off. I realised this upon receiving a tiny shock when groping around to plug it into a different port. I thought it was just sharp at first, but upon being shocked a second time I realised what was happening.

All of the consoles above are hooked up to a 5-in-1 manual SCART switcher ("Thor" branded). They're all using either official or name-branded cables and power supplies. The SFC is hooked up via official JP21 cable plugged into a JP21-to-SCART converter, though I can't imagine that addition would be doing anything. The N64 I bought off an eBay seller though, so I don't know about the quality of the mod.

Current going where it shouldn't feels a little alarming. What's happening here? Should I immediately stop using everything until I figure out what's causing this?

EDIT: After turning the rig off and on again at the wall, problem #1 seems to have stopped, though #2 remains.

[MartyG]

Can't say I'm familiar with the cable mods for the N64, but from what you're describing, it sounds like there might be a capacitor in there somewhere holding a charge that you're shorting to ground when unplugging it. It's all low voltage (12V on SCART cables IIRC) so I doubt it's a big issue especially if you're not getting interference on the signals using it normally.

If you were getting mains shocks that'd be different, but I'd expect you to be tripping RCDs if that were the case and you'd certainly not be getting just a tingle from it.

[speedlolita]

This reads like voltage crosstalk, quite common with certain SCART switch boxes. Not great.

[MartyG]

If there was crosstalk I'd expect signal interference (and I wouldn't expect it in a manual switcher if everything is turned off).

I've looked up the cables now and there is indeed capacitors within the cables themselves, wired in series on the RGB lines: https://www.retrogamingcables.co.uk/...GB-SCART-CABLE

Easy way to work out if it's the switch tho, remove it and just have the N64 plugged into the TV directly, if you're still getting the same issue, it's the cable and it's not something I'd worry about.