2 Is this bad grounding issue?
TL;DR: Just touching the metal part of the hdmi cable to any metal part of the laptop's hdmi, ethernet or usb makes the power adaptor stop working. When I turn the main power off and on again it starts working again.
I got a 1440p 160hz external monitor a few months ago and had to get an hdmi 2.1 cable as older ones I had didn't work properly. It worked fine with the laptop for the past 6 months. Now whenever I connect the hdmi, it stops the power adaptor from working, dropping the laptop to battery mode which significantly affects the performance. I did some troubleshooting and these are what I found out:
- The adaptor completely stops working. Just unplugging from the port and reconnecting doesn't work. Have to turn the main power off and on again to make it work again. If the hdmi is connected, it goes out again.
- I have a 150W adaptor (20V x 7.5A). Didn't get another 150W in time so had to get a 180W from a friend to test. It worked fine with that. I'll get a 150W to test in a few days if needed.
- I connected the laptop to 2 TVs with HDMI cables that were being used with the TVs and it worked fine. Even 4K 30hz and 60hz at a slightly lower resolution worked (these are older cables - "high speed with ethernet" ones compared to the "ultra high speed with ethernet" one I normally use). But when I tried connecting the TV with the HDMI 2.1 I had, the same issue occurs. Edit: just tried with the 1080p TV again with its HDMI cable and the adaptor stopped, so it's not just the other cable or monitor.
- This issue occurs even if the monitor is off. But it doesn't happen if one end is unplugged.
- The display does get output even after all this. Even after it enters battery mode.
- When using the power, without any hdmi connected, the trackpad starts lagging when the laptop hits a higher load. This does not occur in battery mode.
- This is the main point. I opened up the laptop to try clean the ports and when that didn't work, I noticed that just touching the cable to any part of the metal housing of the hdmi port stops the power adaptor. Then I tried touching it to the RJ45 and the USB ports and the same issue occurs. Again this is only if the other end of the cable is connected to the monitor, even if it is off, probably completing a circuit. But I believe hdmi doesn't conduct power through the shell? Correct me if I'm wrong.
What could be the issue here? At first I thought it was either the hdmi cable or the power adaptor but after the 7th observation, I think there's some issue with the laptop. I'm planning on taking it to a repair centre but I'd like to have an idea on what the issue might be and the possibility of if and how it can be fixed.
Ist dies eine gute Frage?
It is definitely sounding like there is power moving over the HDMI cable shielding.
Do you have (or can you borrow) a multimeter?
If so, check for voltage potential between the HDMI metal connector and any of the metal surfaces you have described that cause the issue when touched on your laptop. Do not connect the HDMI cable: do the test with the laptop plugged into power, put one probe on one of the metal surfaces on the laptop and the other on the metal shielding of the HDMI connector (with the other end of the HDMI connector plugged into the TV).
Repeat the test with your other HDMI cables. If you read voltage with the newest cable, there's your problem. The delayed time (the duration in which it worked and you didn't have issues) is either attributed to the time before the cable failed or the time before the undesired voltage caused damage in either your laptop or your power adapter.
If it's the cable: replace the cable. Then repeat the test and verify no more transient voltage.
von Isaac Mehler
Additional note: repeat the test with the multimeter using other TVs. Use this to detect if the issue is with the cable, or with the TV.
Also be aware that older problem A that has been causing unseen problems for a while can then cause internal damage to another component, leading to secondary problem B. This can cause headaches during diagnostics.
von Isaac Mehler
Hi @rgbzd
You said it worked OK with the 180W adapter but not your 150W adapter is this correct?
If so I would check the 150W adapter is OK.
Seems as though the adapter detects an overload condition when the monitor is connected and shuts down (self protection?)
Looking at images of the adapter online it appears that it has a 3 pin AC power plug.
If it has or even if it only has two pins, unplug the adapter from the wall outlet and the laptop and use a DMM to check the resistance between all the pins on the AC plug (individually) and the +ve and -ve pin on the DC output plug.
It should measure >100K Ohms. If less than this there's a leakage problem in the adapter (not sure re the measurement between the AC plug earth pin (if there is one) and the -ve pin of the DC plug.
von jayeff
@isaacmehler Thanks for the reply and I'll be getting a multimeter tomorrow. I have another question... Is power even supposed to be conducting through the metal housing of all these ports (HDMI, USB, Ethernet)? Wouldn't that be the main concern?
von Rgbzd
@jayeff Thanks for the reply. I'll be getting a multimeter tomorrow to test it out
von Rgbzd
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