Finally resolved my black screen issue!
After replacing the Pi 3B, the SD card, the OS, using the latest MM software, much internet searching and a great deal of help through this forum it appears the problem is being caused by the jpg photos being added to the wallpaper module. Changing the photos from large tif files into jpg files using Adobe lightroom creates a highly compressed jpg file that the wallpaper module cannot deal with properly.
Reducing the resolution of the files during the conversion seems to create a less compressed jpg file that the Wallpaper module can deal with.
Hope this helps others with the same issue.

@sdetweil
Thanks for all your efforts and assistance. After many reloads of the OS and the MM software I still have the same issue. After searching for similar Pi problems outside of MM it appears that this can happen due to hardware failure. I am now going to purchase a new pi and start from the beginning. Will report back on success or failure in due course. Thanks to everyone that has offered help and assistance.

BigTJ

@sdetweil
I’ll give that a go in the next few days.
Thanks

@sdetweil
Hi,
Did you have any further thoughts on this problem?

@sdetweil Thanks for the response

I amended the package.json as follows;-

“start”: “DISPLAY="${DISPLAY:=:0}" ./node_modules/.bin/electron --disable-gpu js/electron.js”,
“start:dev”: “DISPLAY="${DISPLAY:=:0}" ./node_modules/.bin/electron --disable-gpu js/electron.js”,

Is this correct?

Yes the mouse still works. Cursor is a black arrow with a white outline. No it does wake up.
Control M works
Control R Works
Control Q works

The start up report of the mirror with minimal content shows;-

magicmirror@2.18.0 start
DISPLAY=“${DISPLAY:=:0}” ./node_modules/.bin/electron --disable-gpu js/electron.js “run”

[11.10.2022 11:45.29.988] [LOG] Starting MagicMirror: v2.18.0
[11.10.2022 11:45.30.003] [LOG] Loading config …
[11.10.2022 11:45.30.030] [LOG] Loading module helpers …
[11.10.2022 11:45.31.926] [LOG] Initializing new module helper …
[11.10.2022 11:45.31.930] [LOG] Module helper loaded: MMM-Wallpaper
[11.10.2022 11:45.31.935] [LOG] No helper found for module: weather.
[11.10.2022 11:45.31.936] [LOG] All module helpers loaded.
[11.10.2022 11:45.32.214] [LOG] Starting server on port 8080 …
[11.10.2022 11:45.32.258] [LOG] Server started …
[11.10.2022 11:45.32.261] [LOG] Connecting socket for: MMM-Wallpaper
[11.10.2022 11:45.32.268] [LOG] Starting node helper for: MMM-Wallpaper
[11.10.2022 11:45.32.270] [LOG] Sockets connected & modules started …
[11.10.2022 11:45.32.942] [LOG] Launching application.
[6000:1011/114533.695740:ERROR:sandbox_linux.cc(376)] InitializeSandbox() called with multiple threads in process gpu-process.

Any further ideas?

Thanks for your continued assistance

@sdetweil Hi, I have changed the line as your suggestion.
The mirror screen is still going blank after a short random period of time.

I have installed the ‘example’ mirror as per your suggestion to a previous query. The mirror works OK and (appears) not to go to black screen. Currently I am commenting out each module in config.js to try to identify if it is a particular module that is causing the problem.

My original set up uses the Calendar module twice (for 2 different users). Is this a possible cause of the problem? ie do I need to have independent modules one per user?

The following lines occur each time I start the mirror. Could this be relevant to my problem?

“[24055:0824/184036.476041:ERROR:viz_main_impl.cc(161)] Exiting GPU process due to errors during initialization
[24096:0824/184036.932766:ERROR:sandbox_linux.cc(376)] InitializeSandbox() called with multiple threads in process gpu-process.”

Thanks

@sdetweil Thanks for the suggestion.

I’ll give it a go and let you know if it is successful.

BigTJ

@sdetweil Hi,
Were the displayed messages of any help in narrowing down the issue?

BigTj

@karsten13

I have another MM running on a Pi 4B that uses all the same modules without a problem.

But I will give your suggestion a try. Thanks for the tip

Big TJ

@karsten13 The modules of the MM are listed below in shortened form. Thanks for your interest.

“alert”
“updatenotification”
“MMM-Wallpaper”
“clock”
“calendar_monthly”
“calendar”
header: “Steve’s Upcoming Items”
“MMM-GoogleSheets”
“calendar”
— header: “Angela’s Upcoming Items”
“weather”
— position: “top_left”
— header: "Currently: "
— location: “Doncaster”
“weather”,
— position: “top_left”
— header: “Forecast”
— location: “Doncaster”
“weather”,
— position: “top_left”
— header: “Forecast”
— location: “Pickering”
‘MMM-WiFiPassword’
“newsfeed”