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Broken Monitor - Damaged DisplayPort Socket

Posted: 12 Sep 2017, 09:10
by BurzumStride

My Acer XB240HA (144hz G-sync) display has stopped working after pulling out the DisplayPort cable too forcefully.
It still shows up as a potential display, but no settings can be saved with any computer configuration, leading me to believe that the some of the DisplayPort's sockets are broken.
The monitor has been opened afterwards, so may not be eligible for warranty, especially since the flaw is not due to a manufacturing defect. So even if they do fix it, they may demand an additional payment.

The DisplayPort in that model is part of the mainboard, which costs £285 (more than the monitor itself).

I stand to lose £40 on shipping if I try to push it for warranty, and nobody is able to give me a definitive answer as to they will even accept it or whether additional repair costs will be incurred (likely very high if they want to replace the whole mainboard).

Has anyone had any success changing or repairing a DisplayPort socket that is integrated as part of a monitor mainboard?

Re: Broken Monitor - Damaged DisplayPort Socket

Posted: 12 Sep 2017, 12:22
by Chief Blur Buster

Yes, sometimes simple repairs succeed but it's a "luck of the draw".

If you think your warranty is now 100% voided, and you already opened it up, check if you can see any visible loosening. Is it surface mounted or pin-mounted?

Ripping a DisplayPort from a circuit board sometimes can be repaired, but it depends on how it got ripped. If it's a simple broken solder joint, it's been quickly repaired in a mere 30 seconds (after spending an hour disassembling & reassembling). Do not attempt this unless (A) your warranty is voided, (B) you have nothing to lose, (C) replacing the monitor is preferable to spending darn near 300 quid. If you meet A/B/C, and have enough decent experience with a quick solder repair, proceed.

If it's surface mounted and you can see the circuit traces (and it's not irreparably ripped off the board, just a detach of two pieces of metal) -- get a very sharp-tip temperature-adjustable soldering iron (chinese generics from eBay are available for $30; good enough for this job) designed specifically for surface mount.

Re-tin the contacts and make the jack connected again. The ground tabs may be through-pin-solder (structural) but the DisplayPort conductors might be surface mounted. If you're worried, get a "surface mount soldering practice kit" (eBay, $5) before attempting to resolder a detached surface-mounted port.

If it's permanent damage to circuit board (cracked circuit board, traces completely ripped from the circuit board, nothing for solder to stick to) -- then you might be SOL unless you're very creative and experienced.

Disclaimer: Do at your risk. We disclaim any permanent damage.

Re: Broken Monitor - Damaged DisplayPort Socket

Posted: 13 Sep 2017, 14:02
by BurzumStride
Thanks very much for the quick response, this sort of information is hard to come across! I'll open it up and have a closer look at the DisplayPort socket and decide what to do next.

Re: Broken Monitor - Damaged DisplayPort Socket

Posted: 23 Sep 2017, 13:24
by BurzumStride
Having taken apart the monitor, I see no immediate flaws in the mainboard:

The monitor powers on, displays the Acer welcome screen and can even be detected as a G-sync capable display as well as identified by both the Windows Display Setting configuration and the Nvdia Control Panel.

However it comes up with a "no signal" error and any attempts to save a display configuration involving it, fail or respond with "These display settings could not be saved" message. This is not a windows-specific issue, as the BIOS screen is not displayed either. The monitor responds briefly to being plugged in and identified, and then proceeds to go into a permanent "sleep mode". I can't seem to access the monitor's OSD or factory menu through the X270 models' keypress combination either, at least not without active input.
I have also tried "power draining" the capacitors by unplugging the monitor for 15-20 minutes, but to no avail.

There have been a lot of "pin 20" issues reported among DisplayPort users, and I was wondering whether that could be a potential cause.
The new cable I used for testing a while back most likely utilises the Pin 20 connection, therefore not conforming to the VESA standards.

An ex monitor-repair-man, mentioned some sort of issue with Acer Monitors only working with the DisplayPort cables included in the box. Upon hearing that, I had another look at my original 1m BizLink cable and noticed one of the pins being slightly bent and void of it's plastic casing that would ensure it was seated correctly, with 2 others being slightly misaligned compared to others (this is only on one side of the cable, probably the one I pulled on).

Both cables give pretty much the same results, and a very sloppy (most likely failed) attempt at isolating pin 20 in the new cable made 0 difference.

I could try one of the VESA certified Accell cables to see if they work?
Or does somebody know how to sort out a mistreated cable?

I am neither ready to give up on the subject, nor particularly excited about trying to add an external dp2lvds board, (like the one from ZisWorks) especially given how the internal DisplayPort socket looks absolutely pristine.


Re: Broken Monitor - Damaged DisplayPort Socket

Posted: 23 Sep 2017, 14:11
by Chief Blur Buster
Question, have you tested a different computer's DisplayPort -- and it didn't work either?

Trying to rule out the GPU side.

Re: Broken Monitor - Damaged DisplayPort Socket

Posted: 24 Sep 2017, 06:20
by BurzumStride
I assumed the GPU side was fine, because the monitor did not work for the guy who originally tried to fix it for me either... although he was using either my HDMI-DisplayPort adapter, or an untested 20 pin cable which were apparently notorious for not working with Acer Monitors.
You may just have found the issue.
Since I have no other DisplayPort outputs that I could test the monitor with, I just quickly used my HDMI to DisplayPort adapter to test the socket in the following configuration:

DisplayPort - adapter - HDMI - Monitor (working 60hz) - "Check Video Cable"
Hopeful I then tried testing the adapter with the working miniHDMI sockets:

MiniHDMI - adapter - HDMI - adapter - DisplayPort - Monitor (144hz in question) - "No Signal"
(after shutting down and booting up also)

Could the weird adapter combination be too much, or is MiniHDMI somehow incompatible with DisplayPort?

If there is a way around having to find someone else with a working DisplayPort output, (which would also require me to purchase a VESA certified cable) in order to reliably test the monitor, I would much rather go down that route.

Re: Broken Monitor - Damaged DisplayPort Socket

Posted: 09 Oct 2017, 04:21
by BurzumStride
The monitor has been tested with a new VESA-certified 2m DisplayPort cable on two different computers, with the exact same issue.
System goes as far as to detect its name and identify it as a G-sync capable display, but any attempts to save any stock or custom configuration fail.

Nothing other than the "no signal error" is displayed after the Acer welcome screen.
"Draining" the power capacitors does not work.

I have tried rolling back to legacy Nvidia drivers, but the oldest version I could get my hands on for the Gtx 770 was 375.70.

Any help at this point would be appreciated, I am out of ideas other than maybe checking the capacitors myself, (though I've had a friend who is more experienced in that area do that for me, and he did not identify any immediate problems) or buying a broken monitor of the same panel, and attempting to swap out the mainboard and power supply.

Re: Broken Monitor - Damaged DisplayPort Socket

Posted: 09 Oct 2017, 16:15
by Chief Blur Buster
It's possible that the DDC/CI signal is failing to make it through.

Adaptors need to properly transcode DisplayPort DDC/CI 2-way communications into DVI 2-way communications. Not all adaptors seem to properly do that.

The monitor needs DDC/CI signalling to trigger & enable G-SYNC, ULMB, LightBoost. They're also an encrypted handshake that also goes on (a form of DRM to protect AMD from not using those features)