Help! My PBP suddenly blacks out completely out of nowhere
#1
Hello,

I have a big problem... Soon we switch from HomeOffice to presence teaching at my professional school and I need a working PBP there. All my past notes live inside Xournal files and I'm very bad at using pens, so I completely relied on my PBP in school.

Since a few weeks, I randomly encounter the following problem:
Out of sudden, mostly when moving the PBP gently the screen blacks out instantaneously, only the backlight stays on. The only thing I may do then is to turn it off via holding the power key.

It isn't just the screen, as I was hearing music lately and it blacked out, the music stopped too and 2 seconds from there my bluetooth headphones played there "disconnected" tts voice.
I also looked at journalctl, but there are no traces of whatsoever. Thinking it may be a loose eMMC or the latest kernel upgrade I grabbed a fresh manjaro image, dd'ed it onto an µSD card and booted from that. It didn't even took me 10mins while configuring the new system to hit the black-out problem :/
Looking inside, nothing seems to be odd, I checked all the connectors, replugged them but that dind't change anything.

Now I'm "at the end of my latin" how you would sometimes say in germany. I don't know what to do now and I didn't find any other mentions of such a problem here or via google. So i may ask: Has anyone any idea how I can fix this, debug this or where to look for further help?

Kind regards,
Jochen
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#2
Do you have a serial console adaptor? I would look for activity there.
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#3
(06-01-2021, 03:00 AM)KC9UDX Wrote: Do you have a serial console adaptor?  I would look for activity there.

Good idea, I will build one in my lunch break in 1,5h. Then I will report back with the results  Smile

Kind regards,
Jochen
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#4
Be careful: there is some discrepancy or confusion about the voltage that the PBP uses for the serial console. I believe it needs to be 3.0V (or less!).

See this: https://forum.pine64.org/showthread.php?tid=9367
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#5
(06-01-2021, 03:47 AM)KC9UDX Wrote: Be careful: there is some discrepancy or confusion about the voltage that the PBP uses for the serial console.  I believe it needs to be 3.0V (or less!).

See this: https://forum.pine64.org/showthread.php?tid=9367

Thanks for the information. The thread itself is a bit confusing, but as I only want to listen for messages I'm going to connect only the TX (PBP) to the RX of my FTDI adapter which does 3,3V and is 5V tolerant. If the RK3399 only does 3V or less on its TX-lne the FTDI will nevertheless interpret it correctly ^^

Kind regards,
Jochen
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#6
(06-01-2021, 01:50 AM)fxk8y Wrote: Hello,

I have a big problem... 
Out of sudden, mostly when moving the PBP gently the screen blacks out instantaneously, only the backlight stays on. The only thing I may do then is to turn it off via holding the power key.

I have seen similar results in a different situation.  I sometimes sit in my armchair with my PBP on top of my MacBook on top of my lap.  If I move the PBP a little, the Hall effect sensor sometimes gets triggered by the magnets in the MacBook.  Any chance there is a random magnet around your set up?
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#7
(06-01-2021, 07:44 AM)tkudog Wrote:
(06-01-2021, 01:50 AM)fxk8y Wrote: Hello,

I have a big problem... 
Out of sudden, mostly when moving the PBP gently the screen blacks out instantaneously, only the backlight stays on. The only thing I may do then is to turn it off via holding the power key.

I have seen similar results in a different situation.  I sometimes sit in my armchair with my PBP on top of my MacBook on top of my lap.  If I move the PBP a little, the Hall effect sensor sometimes gets triggered by the magnets in the MacBook.  Any chance there is a random magnet around your set up?

Nope, it also occurs while holding the PBP in one hand and typing with the other while walking around my flat. Also triggering the hall sensor would mean it goes to standby(which I disabled for compiling software with the lid closed), it would return out of standby when removing any magnets. But this state is a final one which can only be escaped by holding the power key until the PMIC cuts power to the hardware.

Btw. I build the UART-Cable yesterday, but won't have the time for checking the output until evening  Sad

Kind regards,
Jochen
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