Question HP EliteDesk 800 G1 SFF second Display Port not working (blank screen)

[tarmiricmi]

Hello,

I recently obtained a refurbished HP EliteDesk 800 G1 SFF, no dedicated gpu. Inside is i7-4770 with IntelHD 4600 integrated GPU. It has 2 DPs and one VGA port.

Now I have 2 screens that I connect via DP (Full HD resolution both, 60 Hz refresh rate). I can't manage to set up the second display to work. It seems that one DP is not working correctly.
First DP is working with both screens. Second one isn't working with either one (regardless if both are connected or just one to that port).

When both screens are connected, the Windows recognizes the display connected to that problematic DP (with its name, resolution and refresh rate choices etc.) but gives only blank screen on it.

I have another PC, Dell with similar configuration (two DP), and it works without issues on both using the same cables and displays so those two things are excluded as problematic.

Now on that HP I've tried everything:
- BIOS is updated to latest version,
- GPU drivers are updated to latest version,
- no drivers/software conflicts,
- Windows 10 updated to latest,
- generally it functions very well without any other issues (memory and other components tested etc).

Tried clearing BIOS as well. BIOS contains no options regarding DP.
Currently I use it with second monitor connected to VGA and other to one working DP which functions as expected. It is a passable solution but the image looks a bit sharper when connected to DP (as compared to VGA) and there is sound too - not a big deal though.

I've spent a few days researching on the HP's forums and elsewhere and it seems as not uncommon issue on those machines (not only on this particular model but variety of others too), mostly people solve it by adding a dedicated GPU which I may do but still am curious why this happens.

It seems that either motherboard/port connector itself is faulty, I see no other explanation as I excluded all other things. Still I'm posting it here as someone may have (had) similar issue. This machine is old and was cheap to obtain but I saw very recent HP desktops with the same issue.

 

[Lutfij]

I'd try and use DDU to scrub the entire platform off of all GPU drivers, then try and reflash the BIOS with the latest version, then clear the CMOS, then install the latest Intel HD drivers in an elevated command. I'm inclined to think that the OS might be somewhat at fault here but see what DDU + manual driver reinstall, i.e, Right click installer>Run as Administrator, yields.

 

[tarmiricmi]

I'd try and use DDU to scrub the entire platform off of all GPU drivers, then try and reflash the BIOS with the latest version, then clear the CMOS, then install the latest Intel HD drivers in an elevated command. I'm inclined to think that the OS might be somewhat at fault here but see what DDU + manual driver reinstall, i.e, Right click installer>Run as Administrator, yields.

Good suggestions. I already used DDU and cleared previous drivers and then installed latest drivers.
The BIOS is already at the latest version, do you still think it is justified to reflash it with the latest one?

The thing that I'll try out today is to use some USB Linux to see if that makes any difference. Will post here my findings.
Other from that, I'll probably order cheap GPU like GT 1030 with DP and HDMI...

UPDATE: Same issue with latest Linux Mint, booted clean from USB. System detects another display but is blank. Therefore driver issues are excluded. Most likely that DP is faulty OR it could be BIOS issue. There surely will not be newer BIOS updates as this is old machine. I guess I could try to downgrade it or replace motherboard but that would be a waste of time. I'll be adding something like GT 1030 for like 30 USD or so...

UPDATE2: Card ordered 😎