Laptop touchscreen hypersensitive to electromagnetic interference

I have a Dell XPS 15 laptop that's less than a year old and still under warranty. I've been in contact with Dell several times about this issue, but they don't have a clue. The problem is intermittent and looks like this:

My Dell with vertical bars

I have narrowed down the potential cause. I have repeatedly run all the hardware tests and they always pass. When the screen is in this state, I can still hook up an external monitor and use it normally. So the video card is working fine. At first I thought it was due to an unreliable power supply, but the problem continued after I started using a UPS at home and it arises even when the laptop is not plugged in.

I noticed a few patterns as to the problem's occurrences. In the town I live, it almost only happens while I'm at home in the evenings. So both the time of day and the place are factors. I am traveling now and today it occurred for about a half hour while I sat in a coffee shop in the middle of the day. When I got to the hotel in the evening, the problem was severe and wouldn't let up. But after taking a nap and waking up at 1am, after a few tries with turning the laptop off and on, the screen is working perfectly right now.

The only explanation I can come up with is that the cause is external. Since the power supply doesn't seem to be it, then I'm guessing it's electromagnetic interference. I am in Thailand now, until I return to the USA in one month. I don't know much about electricity, but I think it's possible this country doesn't have their electrical grid and wiring under as much control as in the States.

I have to deal with the problem while I'm here. It is super inconvenient to be unable to work on my computer when I don't have the external monitor with me. So what can I do to mitigate the issue?

HappyNomad

Posted 2014-12-22T19:25:16.687

Reputation: 141

what happens if you depress the screen (gently) with your finger close to the dell logo? (it's where I imagine the cabling between the graphics card and the display pass thru). – guido – 2014-12-23T01:01:14.213

I haven't gotten any effect from doing that specifically. But on a related note, after the problem happens but starts clearing up, I can consistently aggravate it simply by folding the screeb forward. This action doesn't normally have an effect. It is only after having the issue then it begins clearing up on its own. – HappyNomad – 2014-12-23T02:28:21.050

Answers

Looks more like a loose cable, or faulty LCD panel, but hard to say for sure. Definitely hardware related looking though.

Since you say an in-line UPS didn't help, and it still happens even when the notebook is unplugged, then it's definitely NOT the AC in your location(s) that are the problem.

Provide your pictures (and explanations of what you've tried already) to Dell and get it repaired while still under warranty (perhaps locate a local official Dell repair partner and go directly there in person).

Ƭᴇcʜιᴇ007

Posted 2014-12-22T19:25:16.687

Reputation: 103 763

Dell insists it's not a loose cable. Anyway, that wouldn't explain the correlation to time and place. As I mentioned, I already tried a UPS and anyway, the problem even happens without plugging in the machine. I already have provided the pictures to Dell and, as I said, they don't have a clue. I can't ask them to repair it when it's not clear what part, if any, needs to be replaced. The screen works fine more than half the time. – HappyNomad – 2014-12-22T19:37:49.467

If it happens even with the machine unplugged then it's definitely NOT the AC in the location you're at. Anyhow, don't try and tell Dell what you think it wrong with it, just show them the symptoms and demand satisfaction under warranty. – Ƭᴇcʜιᴇ007 – 2014-12-22T19:41:31.280

Already tried that. But unfortunately, "demanding satisfaction" is too vague. They were about to send out a repair guy to replace a faulty video card. But I've since confirmed that the video card is working fine. – HappyNomad – 2014-12-22T19:49:57.660

So they offered to try and fix it (by replacing the video adapter, which is possibly the cause, even if your external monitor works), yet you denied them because?? Again, stop trying to guess what's wrong for them, let them do their job in the order they have/want to do it; trust me, I worked for a company that was a Toshiba notebook repair depot for many years, it's the path of least resistance when trying to get this stuff dealt with. ;) – Ƭᴇcʜιᴇ007 – 2014-12-22T19:55:19.470

No, once I told them that the external monitor works then they told me it means the video adapter is okay. I'm all for getting "satisfaction" from Dell. In fact, I want to increase the chances of that actually happening. They are so clueless about this issue, and need any parts for my computer to be shipped from abroad, so I've found it necessary to be more proactive. – HappyNomad – 2014-12-22T20:10:37.620

You can eliminate the possibility of electromagnetic interference by making a Faraday cage around the device. Temporarily wrap it in a single piece of aluminum, leaving air slots, keyboard, and at least part of the screen uncovered. Run the device on battery, unconnected by any cable (e.g. power supply, HDMI, USB etc.) and don't use the touch screen. If the issue goes away, and returns when the foil is removed, it could be EM.

DrMoishe Pippik

Posted 2014-12-22T19:25:16.687

Reputation: 13 291

I would think if there was EM interference strong enough to wipe out an LCD screen, you might want to wrap yourself in that foil. – fixer1234 – 2014-12-25T21:19:09.390