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electric shock help please

cooldan

cooldan

i like pizza
10 Years
Joined
Jul 21, 2011
Messages
7,288
Location
Ealing, London
hi guys, i just got a belter off my South Park when i touched another game and earthed myself.
measuring between the two lockdown bars i got 110V AC

the game was at NLP last year and still has the PAT-test-passed sticker on the plug, dated Oct 2015. where do i look first for the dodgy earth? inside the socket may be a bit outside my comfort zone
 
The very thought of that makes me cringe. First thing I'm doing when I get home is measuring the voltage between 2 machines to make sure mine are ok.
 
Firstly, check that if they have the plug in type mains lead that the lead has an earth conducter. Some cheap crap imports just have live and neutral.
 
I'd say it's more likely that it's the other machine that you touched and not south park - south park merely provided an excellent earth for the current to exit your body hence the belt you got.
 
First thing would be to use a meter and measure resistance between the lock bar and the earth pin on your plug which would demonstrate that you have a good earth or not.
 
the other machine wasn't switched on, so i'm still suspecting SP

there is continuity between lock down bar receiver and top plug prong, showing 35 ohms
 
cooldan said:
there is continuity between lock down bar receiver and top plug prong, showing 35 ohms
Click to expand...

35 ohms is Resistance which I think is high for continuity - does your Beep test work on DMM on the same circuit?
 
I've just checked one of my machines - low Resistance 2 Ohms from lockdown to earth pin, and it 'beeps' indicating low resistance and continuity.

Compare with another of your machines 35 Ohms seems high to me for a good earth.
 
yeah i agree, i was surprised how high it was.
tested it again - 36 ohms
tested two other games - 2.5 and 3.0 ohms.

so i think i need to install a new power lead into the power box, yes? anything worth checking for an easy fix before i do that?
 
I've since measured 3 other machines (busy day :rolleyes:) and they all measure 2-3 ohms even my crusty old Vector project.

I'd be looking for rusty or bad connections on the earth braid links or such like first before replace power cords.

What I don't understand is bad earth aside, does this mean you have a live shorting onto the earth somewhere i.e. once you sort the earth that needs sorting
 
i1352.photobucket.com_albums_q643_shirleyknott_pinball_20Joker26bbcc062f499172d6c16814172760ad.gif

****ing pinball machines, why do we bother?

pinball%20Joker%20Poker%20getting%20thrown%20off%20a%205%20storey%20roof%20by%20Letterman%20slow-mo%20from%20beneath_zps3r9ewxlv.gif.html
 
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I have experienced this kind of problem. With my game it was the actual double wall socket that was defective. One earth pin was fine, the other was intermittently defective. So always worth keeping this in mind
 
Dan. Break it down into small chunks again. Don't replace the mains cable until you've measured the earth resistance from one end to the other. If good then start at that point and measure resistance of the next section.
 
Nope.
uploads.tapatalk_cdn.com_20160624_3c9b0be4fd5a39e064b920e39b1cd5ba.jpg
Ugly but functional and tight, 2.5 ohms to plug earth pin from it.

Power box next
uploads.tapatalk_cdn.com_20160624_67e83f2343cf64f058e2e571ae9fb182.jpg

2.5 ohms also to the post that green earth wire goes to, that earths the power box and connects to the braid. Also to the middle lug on the line filter. And now I'm not getting the 35 ohms from lock down bar receiver to the plug earth pin anymore, just 2.7 ohms. All earth braid seems to be in connection with itself.

So who knows, maybe it was just an earth connector somewhere not properly tightened. Spose I'd better do the electric shock test now.
 
problem not solved, i think Peter was right when he said that the other machine was to blame - there was still 100V AC between the two lockdown bars, and it didn't go away until i removed the power cable to the other game. so now i'm trying to look into that one. it's a kettle lead job (CFTBL) so please, where do i go first apart from trying to establish why Creech isn't properly earthed?

this is the one that blew the fuse in the plug, btw, if that's relevant.
 
i think i'm finally getting to the bottom of it. and i think it is related to whatever happened that blew the fuse in my plug.

at this link http://www.flippers.be/basics/101_sys11_house_fuse_trips.html is this picture -
i put a yellow oval around the bit i think my Creech has blown
ntc02.jpg

here is the power box on my Creech - i made the same yellow oval
Creech power box.png

so i think my NTC thermistor thing has just vaporised (can't find the bits anywhere).

would this explain my symptoms @Moonraker @pinballmania or do i need to look further?

actually now that i look again at the pics, is my existing green disc also wired in wrong?

get @ronsplooter in here!
 
Check the kettle lead first in the same way. What's the socket arrangement,? Are they both plugged into the same outlet, or different. If different then you also need to check earth continuity between the outlets.
 
:sad: after chatting to Andy on messenger and sending him a video, he got me to check out the two sockets, and i have a major problem where there is 92V AC between two sockets so my house is a deathtrap :-o
 
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