External Dual Monitors and Laptop screen issue EliteBook 840/850 G3 and 2013 UltraSlim Dock

[Corncob75]

Hi SherryJ,

Scroll back to page 2 of this blog, last post is mine describing the issue.

http://h30434.www3.hp.com/t5/Notebook-Video-Display-and-Touch/External-Dual-Monitors-and-Laptop-scre...

Definitely cellular interference, we have the internal module with a 4G SIM in it, from testing it is worse when the reception flicks between 3G and 4G.  Here in Australia this is a regular occurrence, especially if a Kangaroo comes bounding past the computer 🙂

We have not replicated the Mobile phone interference.  But if you remove the SIM from the WWAN module the issue goes away.

I will hazard a guess that the newer mainboards have more/better shielding or they’ve fixed the frequency of the Skylake processor and therefore they aren’t susceptible to the interference.

[someone123]

good luck. and let us know if the new mobo fixes the issue.

[SherryJ]

We don't use the SIM so that is not the issue for my company here in the US.  Mine did it again today some and has the shield and my phone is at least 6 ft away.  : /

[zvm76]

you guys, after reading all the posts - looks like G3 two problems. in some units you can see both of them present, in some - only one. looks like in some cases it has nothing to do with interference with skylark. did you notice where the sim card slot is located? righ above HP dock station port. when you on dock station, and sim card in the slot - you have problem. at the same time, stand alone PC (not docked) with sim card - no issues.  Wneh you use thrid party dock station, like targus or any other and use sim card - no issues at all.  so, it is not the skylark, at least not in 100 percent of the cases.  when got mobo replacements - did anybody notice actual screens of skylark or any other changes - dock port for example screening?

[SherryJ]

I'm not sure I understand everything zvm76 is talking about.  We have no SIM cards installed.  It might be worth trying a different brand of docking station though because, as strange as this sounds, if my monitors start blinking, if I just hold the dock and gently make sure my computer is docked properly, the blinking stops ... no cell phones around.  My laptop does have the CPU shield. 

[thumathd]

Our G3's dont have the SIM module so have never had a SIM card installed

we have the problem..

[Corncob75]

Sorry for the delay, HP came last Friday and replaced the MB in our affected machine (the one that we could replicate the issue on easily).  Since that change the issue has not returned.

I had a meeting with their Tech's and our BDM on Monday, they confirmed that the original MB's required the shielding where the newer ones do not, the newer ones have 2 additional capacitors that prevent the "Bridging" of the GPU component of the Skylake processor with the signal from 3G cross 4G change.

Cellular phones in the room can also cause this "Bridging".

They were surprised that the shielding didn't work initially on the machine here.  But hey Mainboards all round 🙂

Hope it helps.

On to the next issue with the 800 G2 Mini !!

[SherryJ]

Thank you for the update Corncob75!  The new MB's sound promising!  Please keep us posted ... the shield worked for a couple of weeks so I won't claim victory yet.  Not trying to be negative ... I am very hopeful that this works!

[SherryJ]

Concob75 - any updates this week?

[SherryJ]

@Corncob75 - how are you certain that the motherboards to be replaced are new?  HP said they can not guarantee I will get the most current as replacements.