Hack Forums
Dual Monitor Display w/ Laptop (Ground Loop? Problem) Constant Flicker - Printable Version

+- Hack Forums (https://hackforums.net)
+-- Forum: Tech (https://hackforums.net/forumdisplay.php?fid=444)
+--- Forum: Computing (https://hackforums.net/forumdisplay.php?fid=88)
+---- Forum: Computer Hardware (https://hackforums.net/forumdisplay.php?fid=87)
+---- Thread: Dual Monitor Display w/ Laptop (Ground Loop? Problem) Constant Flicker (/showthread.php?tid=5775790)



Dual Monitor Display w/ Laptop (Ground Loop? Problem) Constant Flicker - J. McCarthy - Dec 28, 2017

Whatsup guys. So I have an odd problem

I have 2 external displays hooked up to my laptop 1 via HDMI and 1 via lightning to HDMI.
It works perfect when the laptop is not plugged in. However, if I plug my laptop charger in while using the external displays (only both, one or the other works fine) then the screen randomly flickers to black and spazzes out moving stuff all over. If I unplug it then it goes back to fine.

Any ideas what the issue is?   My laptop is an Asus Zenbook.

I read similar issues where this is the "Ground loop effect" however both monitors are only two prong plugs and don't have a ground on them (when the normal fix is covering up the ground on a 3 prong)


Any ideas?


As soon as I plug the charger in is when the flickering begins:
[Image: 56247677293f9207bf6bc95ddf0a8cbc.gif]



I have both monitors plugged into a wall outlet and the laptop charger in a separate one.


RE: Dual Monitor Display w/ Laptop (Ground Loop? Problem) Constant Flicker - webdev77 - Dec 28, 2017

Do you still have the issue if you use a 3-prong to 2-prong adapter on the laptop power brick?


RE: Dual Monitor Display w/ Laptop (Ground Loop? Problem) Constant Flicker - J. McCarthy - Dec 28, 2017

(Dec 28, 2017 02:40 PM)webdev77 Wrote:  Do you still have the issue if you use a 3-prong to 2-prong adapter on the laptop power brick?

I don't have any 3 to 2 adapter to try it with -- I just noticed neither monitors had a prong so wasn't sure why it would have mattered I guess.

Will doing that fry my computer or something lol


RE: Dual Monitor Display w/ Laptop (Ground Loop? Problem) Constant Flicker - datguy.dev - Dec 29, 2017

Normally, when you plug in the laptop, the power plan changes. Try setting it to high performance in the power options for both with and without wall power. Also try booting the computer with the charger and displays all connected.


RE: Dual Monitor Display w/ Laptop (Ground Loop? Problem) Constant Flicker - J. McCarthy - Dec 29, 2017

(Dec 29, 2017 07:08 PM)datguy.dev Wrote:  Normally, when you plug in the laptop, the power plan changes. Try setting it to high performance in the power options for both with and without wall power. Also try booting the computer with the charger and displays all connected.
Tried the power plan - Will try rebooting


Rebooting didn’t work either unfortunately once the second display syncs up after I login it starts spazzing out


RE: Dual Monitor Display w/ Laptop (Ground Loop? Problem) Constant Flicker - J. McCarthy - Dec 31, 2017

Any other ideas on how to fix?


RE: Dual Monitor Display w/ Laptop (Ground Loop? Problem) Constant Flicker - datguy.dev - Dec 31, 2017

(Dec 31, 2017 08:10 AM)Formula1 Wrote:  Any other ideas on how to fix?

With the AC unplugged so you can address the monitors, try going through and setting the refresh rate on all monitors to the same frequency. Then plug in the AC. If it flickers again, try the other frequencies if they're support on each monitor. (i.e all 50 Hz. or all 60 Hz.) To change the refresh rate, you have to open the devices advanced properties. Under the monitor tab, you'll find the option. 

If you have a UPS, it maybe worth a shot to put the laptop and monitors on it as that can smooth various electrical irregularities. I looked up your problem and I've seen a few say a ground loop isolator helped... I've used those to sort out audio noise. The only problem there is its not a guaranteed fix.