Odd Issue

[CzarD0mn]

So, here it is.
Manjaro Phosh, 3G_RAM/32GB_STORAGE PinePhone board.

After discovering that my pinephone stopped charging, I tore it down to see the main diode on the usb-c board blew. Replaced it and started charging. But now I can not keep convergence active on any external display using, a NexDock lapdock(usb-c to usb-c alt mode), an Anker HDMI dock, or the official pinephone dock. The external display just flickers and will not stabilize. A quick connect, disconnect, repeat issue. I thought I may have fixed it by tearing it down and unplug, then reapply the ribbon cable on the usb-c board and main board.
External displays worked again, or so i thought. Cut to class today. screen kept flickering, so I switched out my SIM card to my backup android phone and tried to dock it again, it worked.

The thing that baffles me is this, any other peripheral works without fail, (ie flash drive, mouse, keyboard)

After trying this multiple times, using an external display will ONLY work without the SIM card inserted.
I switched off the WLAN DIP, SIM inserted, wont work. WLAN DIP switched on, no SIM, convergence works flawlessly.

Should I just get a new mainboard, as I am thinking the diode didn't blow soon enough before some extra voltage screwed up the main board.

[alaraajavamma]

Hello!

Do you get some info from dmesg?

It is kind of known issues that mobile broadband causes some problems to HDMI out.
Kind of because it is somehow rare and not documented (my guess is most likely because people are still using PP/PPP as testing/developing machine rather than full time daily use convergence thing so they don't notice this)

And this is absolutely strange - for example my case:
Most of the places "convergence aka. external display" is absolutely unusable if I am using 4G network.
After switching to 3G, 2G or turn off mobile broadband external display works perfectly.
BUT I have one place where I can use 4G network and external display works without flickering etc.
So it is somehow related to radio frequency and cable protection or something.

I have 6 Pinephones and so many docks and monitors that I can't even count. On every device there is this same problem no matter what OS/Modem firmware etc. there is running

[CzarD0mn]

I think it was something with an update. I run $pacman -Syu each week to get the latest fixes. Well, I wrote the Manjaro Phosh Beta 23 to emmc. The issue was not present, when I updated using $Pacman -Syu, something broke. I'll dig more into the issue as I now believe this is a software issue. I'll delete this post as I posted it incorrectly as a Hardware issue.

EDIT:

So it is a hardware issue. Sorry for the flip flop.

Does the Modem radio frequency affect the HDMI Frequency? Reason I ask is with nothing done, Convergence works fully now using Manjaro and PmOS. Is there a way for me to see which Modem band I am currently using? I am curious as to why this issue is present at certain times.

[alaraajavamma]

Does the Modem radio frequency affect the HDMI Frequency? Reason I ask is with nothing done, Convergence works fully now using Manjaro and PmOS. Is there a way for me to see which Modem band I am currently using? I am curious as to why this issue is present at certain times.

Modem radio frequency is doing something to HDMI Freguency  - yes

I am also trying to learn so can't give you good answer.
There are some options and commands in modemmanager where you can choose and most likely see current frequency but as said I am also learning as I write. I can tell you if I find out how