External monitor flicking when connected to HP Thunderbolt Dock 120W G4

[BEH24]

Hello,

my problem is that when my laptop (HP Zbook Power G10 A) is connected to my HP Thunderbolt Dock 120W G4, and I power it on, the external monitor (Samsung C49HG90DM) after a while starts to flicker, and then this happens every 2 minutes. The monitor goes black for 3-10 seconds, and then the picture appears again, though sometimes it stays black for a long time.

Between the HP Thunderbolt Dock G4 and the monitor, I'm using a DP ver. 1.4 cable.

I have updated the firmware on the HP Thunderbolt Dock 120W G4 and checked the option to use a high-resolution monitor in the laptop's BIOS.

Everything functions flawlessly when my laptop is connected directly to the external monitor, so I'm pretty sure there's an issue with the docking unit.

Does anyone have any suggestions for a solution?

[Jupitero]

Hello.

This sure sounds like a problem with the dock.

Nevertheless, I would recommend upgrading also the laptop BIOS (if you didn't already - not mention of it).

I would also recommend trying with another DP cable. Perhaps the laptop has just that much better DP signaling than the dock, so that your cable works. There officially are no "DP v1.4 cables" - check the cable for "HBR" markings instead. The Displayport wikipedia article has good information about DP cable certifications. In any case I would expect Samsung to pack a good quality cable with the display.

Your Samsung display is 3840x1080 @144Hz 10bpc = 25.66 Gbps bandwidth. A cable not certified for HBR3 may still work fine. Check also the Settings settings for DSC or Display Stream Compression and enable it if it wasn't already. DSC greatly reduces the bandwidth requirement.

If you happen to use the display in less than optimal settings, e.g. 8bpc and/or 60Hz - does it still blink?

If you can't get the display working with these methods, I recommend contacting HP about a product replacement.

[PLeung415]

Do you have anything else connected to the dock?  I have the same problem with flickering, but I connect the dock to HP E27k G5 monitor.  I also have problems with everything connected to the dock including network, keyboard and anything connected to the dock.

After I check the connector (the end of the cable connect to the notebook), the problem is the connector, so try this,

Check this AFTER disconnect any harddisk:

- Slightly and gently touch the cable.  Your monitor might flicker right the way.

- Connect and disconnect the cable.  It usually fixed the problem for few days.