A Shocking Surprise from my P150hm!

At work, I literally use my laptop on my lap. I leave it plugged in most of the day and find that when I pick it up to get out of my seat, I get a little electrical tingle out of the air vents. It seems to only happen when the charger is plugged in, and mostly out of the bottom air vents but sometimes out of the side.

Since the problem started, when I have to get out of my seat I've resorted to closing the lid, waiting for it to go to sleep, unplugging it, moving it while trying to only hold it on the sides, and plugging it back in when it is placed down again. Has anyone else experienced this? Is this a defect or something that is normal that I just need to be careful of? I can't help but worry that it has potential to damage some of the components when it's transmitting electricity to my fingers. Any advice?

 

Well it could be two things. The first (especially for this time of year) is that it's just static discharge due to the dry cold weather. You just touch a metal part of the chassis and you get a little shock, just like you would running your feet across the carpet. This isn't great for the machine, but it doesn't necessarily indicate a fault. Just try to ground yourself on something metal before you pick it up.

The other possibility is that there's a short in the machine somewhere, but I've never seen or heard of this happening.

 

It's definitely not a static discharge as it's a constant tingle rather than a quick zap. It also only seems to happen when the power supply is plugged in. I received it from you guys in December, should I start a ticket?

 

are your main's earth properly grounded? have you tried another power socket? or are you using a 2 pin power socket

 

It has happened on multiple outlets, some of which I know for certain are properly grounded. However, there may be a problem with the internal grounding in my power supply; it does tend to spark quite a bit when I plug it in, even when it's disconnected from the laptop.

 

I've been playing around and testing the conditions a little more which produce the shock, and the most consistent way to produce it is when I am holding it while plugged in to the charger and it goes to sleep. If I'm holding it at any vent point at all, the instant the computer finishes going to sleep it delivers a fairly sharp shock, and it's definitely not the same as a static discharge. Hope this helps, I would love to figure out why this is happening if anyone has any advice!

 

a sharp shock sounds like a capacitor discharge to me.

have you tried doing the same without the battery? meaning sending the laptop to sleep without the battery inside only the mains

 

Yup, did it just now with no shock with the power supply disconnected, but happens every single time that I do it with the power supply connected.

 

I think he meant shutting down the laptop, removing the battery, plugging the ac cord in, booting it up without the battery and see if you can reproduce the issue.

(rules out the issue with the battery)

 

I think I had this problem as well when I had a Sager, but to be honest I didn't get any shocks from the laptop itself. ( Just the sparks from the plugs. )

Does the OP hear some whining noises from the laptop itself or the power supply?

Usually when a capacitor is faulty, it has a significant amount of whine that can be heard due to a high-frequency discharge.

 

^^ this....

 

My mistake. I just did that and no shock. Does that mean I have a faulty battery? Sorry for my lack of expertise, this is my first laptop.

No unusual sounds or whining from either the laptop or power supply, just the electrical discharge and the sparking when plugging the power supply in.

 

Hi everyone,

This has happened to me (precisely when the docking connector or exposed metal in the chassis rests on my bare thighs), and while annoying it's nothing to worry about. Allow me to explain with an over-simplified diagram of a switching-mode PSU (power brick), mains input to the left and DC output to the right:



PSUs are mostly insulated, but it's not unusual to have a *tiny* "Y capacitor" across the transformer as seen above (something about reducing interference), which provides a very high-impedance path from mains to the DC plug. Thus, your laptop's circuits and chassis are not entirely "floating" and you may get this slight tingle in sensitive parts of the skin. Due to the high impedance, it's unlikely that the current will reach the 5 mA or so required for actual physiological effects (see http://www.allaboutcircuits.com/vol_1/chpt_3/4.html).

TL;DR: if you only feel it in your thighs and other sensitive skin, you're not going to get electrocuted. Call it a "design limitation"

(I thought I'd make my first post a useful one)

 

Thanks for the input. That is helpful for the occasional tingle, although the powering down into sleep mode shock I get is definitely more than annoying, it can be downright painful. It definitely doesn't seem like something that should be happening, anyone else have anything to mention now that I seem to have narrowed down the problem to something battery related?

 

Were I you, I wouldn't buy a new battery only to discover it doesn't solve the problem. While it may just be an annoying, albeit painful, shock now it may well turn into a short later.

You should call your retailer or sager directly, and get an RMA.

As a retailer, we like to keep up to date on all our customers issues. It makes it easier to handle any future cases; so I would call your retailer first, and have them issue an RMA on your behalf.

Best of luck!

 

Whoops, then it's not the Y-capacitor leaking, and no, it's not normal.

If I read correctly this time, you get the shock when the power brick is plugged and the battery is place.
The battery is hardly the source of the shock (~15v). On the other hand, switch mode PSUs are tricky: a (defective?) battery can make it produce spikes if the regulation is wonky, and the (-) output is most likely connected to the chassis ("ground"). So the PSU is bad and perhaps the batt is too. Not worth the trouble if you're still under warranty.

Ditto. Your rogue PSU is likely to turn worse. Talk to your dealer; maybe you only have to send the PSU and battery back if shipping costs worry you.

 

Alright, ticket submitted, I'll update the thread with what I find. Thanks for the advice, everyone!

 

Final update, after about 3 weeks without my laptop's power supply I finally got my RMA'd brick and it seems to have fixed the issue. Hope this can help someone else out in the future.

 

You mailed your package back to us on Feb 25th. We received it on Feb 29th, and mailed out your replacement on March 5th, which was 3 business days later. Your replacement would have arrived on the 8th, but your addressed changed from the one on your order, so we had to redirect the package from Texas to California.