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Laptop Mains adapter working but faulty

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Tipsy

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I have an adaptor for Toshiba laptops - converts three pain mains 230vAC to 2-pin DC16V @6A

It powers the laptop as it should but if I brush anything conductive on the laptop I get a shock. Additionally, if I connect another mains powered device to the laptop, as soon as I make the connection, the mains ring circuit breaker trips.

Is it something that can be easily fixed and if so, would anyone care to guide me? Even if not, I'm interested in the cause of this as it's not the first device I've been shocked by.
 
it's not the first device I've been shocked by.
It's highly likely that your mains plug (on the wall) is miswired and there is nothing wrong with the laptop. From your symptoms, the live wire is swapped with the neutral and/or the ground.
 
It powers the laptop as it should but if I brush anything conductive on the laptop I get a shock. Additionally, if I connect another mains powered device to the laptop, as soon as I make the connection, the mains ring circuit breaker trips.
This sounds very suspicious.
I assume that the mains circuit breaker is an RCCB (Earth Leakage) type.
Does the mains cable to the laptop PSU have a three pin connector at the PSU or just at the mains end.
I have a couple of old laptops with two pins into the PSU and it is sometimes possible to get a "tingle" due to the stray capacitance across the transformers in the PSU, but no way should this be causing the mains circuit breaker to trip.

When you say "shock", is that just a tingle or a "ouch yer ba***rd" type shock which gives real pain?
You say this is not the first device which has shocked you, were they plugged into the same socket as the laptop?
If it is you could have a serious wiring problem in your house.

JimB
 
I'm surprised you haven't killed the laptop, or that it even functions with whatevers going on. It sounds like you're feeding your DC power supply two phase power but no ground, so the entire supply is floating above ground, which is why you're getting zapped. Either the house is miswired or the adapter is, you need to stop using it immediately before you kill someone, start a fire or just generally destroy the hardware.
 
I elimintated power cord and laptop by replacement so it's definitely the adapter itself. The power cord is a typical 3-pin mains plug with fuse to a figure-of-eight two pin outlet - these are quite common, universal cables used for many consumer devices.

Although I said the adpater powers the laptop fine, I just got it out again to double-check my facts and it's not working at all now. Seems a shame to scrap it as I'm sure there's some useful components still functioning on-board, if not the majority of them. Is it not worth repairing?

The shock I got from this adapter is a sharp, pull your hand away quickly type that probably arced to my skin rather than me making firm contact. I would say it's equivalent in quality to the discomfort I get putting a 9v battery on my tongue.

When I say I've had shocks before, I meant, in my lifetime (various locations/units) For instance, I noticed some PC chassis's will give me a tingle when touching a plugged in unit. I'm very curious to understand how this occurs and why it doesn't blow the fuse in the plug, especially if it trips the breaker in the consumer box. I'm confident the mains wiring is good and no other faults are present in my household.


 
I hate to throw away potentially useful items when they can re-used or repaired, does no-one think it can be repaired? If anything, it would make an ideal source for my DIY adjustable power supply.
 
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You might want to confirm there is no break in the ground wire inside the power cable.
Test it with a continuty meter of your multimeter.
HTH
 
I'm surprised you haven't killed the laptop, or that it even functions with whatevers going on. It sounds like you're feeding your DC power supply two phase power but no ground, so the entire supply is floating above ground, which is why you're getting zapped. Either the house is miswired or the adapter is, you need to stop using it immediately before you kill someone, start a fire or just generally destroy the hardware.

The UK doesn't use the strange two phase system the USA does, it's three phase with only one phase and neutral supplied to each house (and three phase to industrial users).

There is a slight chance the socket on the wall is wired incorrectly - but getting earth and live the wrong way round would require some SERIOUS stupidity. All plugs now are moulded, so unless it's been chopped off and replaced, that can't really be wired wrong. It could well be there's been a breakdown between primary and secondary in the PSU? (which would be VERY unusual) - and in which case the earth lead from the plug can't have been used, it may be a double-insulated unit?.

If it is a double-insulated unit, then there may be nothing wrong - it's supposed to have a slight leakage, and is normal - it could be that the earth leakage trip is faulty, and far too sensitive (I've known them fail like that).

But I would seriously recommend getting it checked - you can't gauge degrees of electric shock from personal descriptions :D
 
As previously stated, it is a two pin device (fed only live and neutral I presume) - the common figure-of-eight type (see photo of socket above if my description isn't clear). Incidentally, I have never understood how doing away with the earth for this common type can be considered safe but I'm no electrician.

Oh well, if it's got you guys stumped then I guess there's nothing more I can do other than break it for parts?
 
Like I said, if it's double-inulated (which you'vr confirmed it is), then it's going to give you slight shocks, it's designed that way - to prevent bigger shocks from static discharge.

Taking out your trip could easily be a faulty trip - easiest test is to get the PSU PAT tested.
 
Hi Nigel, sorry I don't understand the implications of double-insulated but it sounds good. Unfortunately, I don't know how to PAT test nor know anyone that would do it for free as any testing costs would be better spent on a new adapter.

When it was working and, for instance, I connected an RCA plug from a projector to the TV out (RCA socket) on the laptop I witnessed it arcing between the conductors at which point the mains would trip (and nothing else has ever caused a trip) which makes me doubt it's the breaker at fault but I'll look into that possibility now you mention it.
 
When it was working and, for instance, I connected an RCA plug from a projector to the TV out (RCA socket) on the laptop I witnessed it arcing between the conductors at which point the mains would trip (and nothing else has ever caused a trip) which makes me doubt it's the breaker at fault but I'll look into that possibility now you mention it.

Like I said, it's a fairly common problem - if the trip is over sensitive, then the sudden connection of a double-insulated device to ground can make it trip.

If you have a multimeter, then try measuring resistance between the mains pins on the PSU, and the output - it should be very high. This isn't a very good test, for PAT you use 2500V or so.
 
Using the 2000K range, I cannot get a reading at all between the input and output pins but as previously advised, it is now a non-working adapter.

For future reference, are the breakers swappable (observing safety precautions and their ratings of course) between rings?
 
That is (was?) a fake / copy of the original power supply. The metal strips beside the heatsink are just there to make it weigh about what the real one would.

It sounds to me as though the insulation between the 230 V side and the 19 V side broke down. Then when you connected the laptop to anything earthed, current would flow from the 230 V side to the 19 V side, then to earth and trip the breaker. There should be no current at all, and quite a small current, maybe 30 mA to trip the ELCB. The plug fuse will be 3A or so, and if the fault current is less than that, it won't blow the fuse, just trip the breaker.

Buy an origianl power supply, although it is difficult to tell the difference without a hacksaw or an X-ray machine.
 
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Diver300 I think you've hit the nail on the head and it makes perfect sense to me. I bought a used laptop and that adapter came with it. Something was rattling inside and when I opened it, a blob of glue fell out. This made me wonder if it had previously been repaired and my query into repairing it again. I noticed those steel plates just taped together doing nothing. Now I know!

So it's decided for sure now, I'll break it for parts.

Thanks everyone for their input, case closed.
 
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