USB-C to Display Port is ruining my life

happyhippo1337

macrumors regular
Original poster
Jul 3, 2013
198
74
Hey there !

I've a 2018 MBTP 15'' and want to connect it to a Dell AW3418DW via USB-C to display port.
That works in general. But the display constantly goes dark - mainly when the air conditioning turns on, or when I get up from my chair. It's a spring-loaded Ikea Markus chair and these chairs develop a magnetic field that get's somehow discharged when getting up from it or sitting down again.

HDMI connection is not affected, but the Dell only has HDMI 1.4 so I would only get 34440x1440 with 50 Hz instead of 60 or 120. I'd be ok with 60 Hz, but 50 is really sluggish.

The monitor is not the problem, all other displays have the same issue when connected via USB-C to display port. I hooked up a friends MacBook and it had the same problem.

I then tried out different cables, one that was pretty expensive and said to have a very good shielding. Same issue. I even bought ferrite cores and put 10 (!) of them on the cable to mitigate the issue. Same result.

Is anyone here experiencing the same issues? This is really driving me mad.
 

1096bimu

macrumors 6502
Nov 7, 2017
319
286
"The monitor is not the problem, all other displays have the same issue when connected via USB-C to display port. I hooked up a friends MacBook and it had the same problem."

Let's use the power of deduction and deduce, what else might be the problem here?
It's not the computer
It's not the display
maybe... if only there was something else.... hummm something else in-between.....
 
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Kenny99

macrumors newbie
Jan 28, 2018
29
3
ST. Louis, Mo.
You mention "But the display constantly goes dark - mainly when the air conditioning turns on". Have you looked at plugging your monitor into different outlet. What I mean is the current for the outlet (circuit) could be dropping as when the Air Conditioning tuns on (it pulls a lot of Current to start but then drops to its running current). What else have you got plugged into that outlet?
As a rule of thumb in counting devices on a circuit you count each outlet (light or receptacle) as 1.5 amps. Now remember you only count 80% of the rating which means a 15 amp breaker should not exceed 12 amp load, a 20 amp breaker would be 16 amps.
When checking this don't forget that your room lights may be on the same circuit as the wall outlet. If your not that fimular with house hold electric then i suggest that you just run an extenuation cord for the monitor to another outlet in a different room as a test.

KenK
 
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BrianBaughn

macrumors 603
Feb 13, 2011
6,365
938
Baltimore, Maryland
You may not solve this until you get some sort of power conditioner or UPS (uninterruptable power supply).

What's your source on the Ikea Markus chair magnetic field issue? Weird!
 

Painter2002

macrumors 65816
May 9, 2017
1,083
759
Austin, TX
I'd test out a new quality USB-C to DisplayPort cable... A lot of cheaper cables (especially those from no-name brands on Amazon) will have issues with lack of proper insulation that would prevent interference from the chair.

Also, have you tried plugging the monitor into a different outlet? If you have too much plugged into the single outlet (say using a surge protector), then it maybe using too much juice, and causes the outlet to trip. If you are using a surge protector, I'd also check to make sure that is functioning correctly and wasn't damaged from a power overload or surge.

Odds are the issue is not with the computer or monitor, but the cable/outlet/surge protector.