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Horrible screen flicker/strobe on battery power - Printable Version

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Horrible screen flicker/strobe on battery power - mattjb - 11-02-2019

Moving my information to its own thread here from the General Discussions forum as it seems like at least one other person is having the issue too. I'm thinking it is hardware related as it happens on bootup before it hits any graphical intensive tasks or a desktop. I can only adjust the brightness when  in desktop mode though, as it seems to be handled through the power management application.

Quote:I'm experiencing the exact same issue as Meatball regarding the flickering screen when on battery. When on AC power, it's fine, but as soon as I unplug it, any graphical related activity (even moving the mouse) causes random massive headache-inducing flickering. It seems to get worse as time goes on... It is still present with all dimming options off and happens at any brightness level as far as I can tell. I'm also hearing a high frequency whine when it switches to battery power though I haven't paid attention if it happens at different brightness levels. It's happening on both the default Debian install and on ayufan's rock64pro bionic-mate-pinebookpro-0.9.14-1159-armhf. I'll report back on other observations I make regarding this issue.

An update on the screen flicker:
Played around with the brightness a little to see the effect and here and these are my observations on brightness levels while on battery power only...
0: no coil whine, no flicker, but absolutely too dark to see anything worthwhile
1: bad coil whine, no visible flicker, usable, just a bit dim to liking
2: horrible continuous flicker/strobe - completely unusable
3: flicker but better than 2
4: a little better than 3
5: as bad as 2
6: better than 5
7: same as 6, just brighter
8: random flicker (1-2 per second), not continuous (fractions of a second) like levels 2-7
9: horrible flicker/strobe
10: worse than 9
11: worse than 10
12-22: same as 11, just brighter, completely unusable

The flicker/strobe is also visible in non-GUI applications, like when Ctrl+Alt+F1'd
For tracking purposes, battery level is being reported as 52%. I haven't had a full discharge yet.
I'm in the process of trying to drain the battery before a full recharge to see if that fixes it, just taking a while on brightness 1.
Could it perhaps be a defective battery? Any way to test this?


RE: Horrible screen flicker/strobe on battery power - mattjb - 11-03-2019

An update: Had the opportunity to fully drain and recharge the battery to full. Looks like that has fixed the flicker at max brightness. Will continue to monitor (no pun intended) over the next few days to see if it acts up again when battery gets low.


RE: Horrible screen flicker/strobe on battery power - Arwen - 11-03-2019

I saw the screen flicker at what I thought was about 50% battery, (>4 hours).

Decided to drain the battery, so I put it aside running. Within minutes, screen went black and power LED turned off. Could not restart it. So I pugged it in, to charge. That brought functionality back, and no flicker so far. But, the initial charge did not last as long as I expected. (Of course, it could have been the 30 minutes of stress tests while on battery...)

Perhaps the flicker is due to low voltage, when the battery is close to being drained.


RE: Horrible screen flicker/strobe on battery power - Meatball - 11-04-2019

(11-03-2019, 11:44 PM)Arwen Wrote: I saw the screen flicker at what I thought was about 50% battery, (>4 hours).

Decided to drain the battery, so I put it aside running. Within minutes, screen went black and power LED turned off. Could not restart it. So I pugged it in, to charge. That brought functionality back, and no flicker so far. But, the initial charge did not last as long as I expected. (Of course, it could have been the 30 minutes of stress tests while on battery...)

Perhaps the flicker is due to low voltage, when the battery is close to being drained.

I highly suspect it's due to voltage/current/power problems. My pbp never flickers while above ~70% battery or while connected to the wall. flickering when @ around 10% is horrible. @ mid brightness my problems worsen but the lowest visable setting is the best (very dim though). either our screens consume more power (bad samples) or the battery have trouble providing the neccesary current or both. Since my problems have diminished over this past week it seems the battery is part of the problem at least.


RE: Horrible screen flicker/strobe on battery power - cowsay - 11-04-2019

This should probably be moved to the main PBP forum instead of the accessories subforum. Sounds like a pretty major issue.. I'm curious how many people are dealing with this? I've seen a lot of posts about display issues


RE: Horrible screen flicker/strobe on battery power - fire219 - 11-04-2019

(11-04-2019, 12:21 PM)cowsay Wrote: This should probably be moved to the main PBP forum instead of the accessories subforum.  Sounds like a pretty major issue.. I'm curious how many people are dealing with this?  I've seen a lot of posts about display issues

This is the Hardware and Accessories subforum. It's in the right place. Smile

This is a concerning issue though. Would be interested to hear from more people as to if they have this issue too.


RE: Horrible screen flicker/strobe on battery power - mattjb - 11-04-2019

On first discharge still since full recharge. Started getting occasional "blinks" every minute or so while browsing, and as I hit 90% battery, the flickering began at ~50% brightness. Dropped brightness down to 3rd level where it's back to an occasional blink, but not a continuous seizure-inducing nightmare. I'm noticing that there's a distinctly audible coil whine as the flickering starts, and then all of a sudden stops when the flickering stops (until it starts again).


RE: Horrible screen flicker/strobe on battery power - Meatball - 11-05-2019

(11-04-2019, 05:51 PM)mattjb Wrote: On first discharge still since full recharge. Started getting occasional "blinks" every minute or so while browsing, and as I hit 90% battery, the flickering began at ~50% brightness. Dropped brightness down to 3rd level where it's back to an occasional blink, but not a continuous seizure-inducing nightmare. I'm noticing that there's a distinctly audible coil whine as the flickering starts, and then all of a sudden stops when the flickering stops (until it starts again).

In my case setting the CPU to 400mhz really helps which also suggests a power issue!


RE: Horrible screen flicker/strobe on battery power - Meatball - 11-06-2019

I contacted the sales team about the issue and got this response from the engineering team :

"Hello <meatball>, 

We suspect the issue is happened on the main board.
Please ship the 1 x Pinebook Pro defective board(only the main board) to below address  

... 

Once we receive the board we will do the testing. 

Your understanding and patience is greatly appreciated.

support team#2..."

Thinking about it out makes sense as the board is what delivers power to the screen..


RE: Horrible screen flicker/strobe on battery power - mattjb - 11-06-2019

(11-06-2019, 09:04 AM)Meatball Wrote: I contacted the sales team about the issue and got this response from the engineering team :

"Hello <meatball>, 

We suspect the issue is happened on the main board.
Please ship the 1 x Pinebook Pro defective board(only the main board) to below address  

... 

Once we receive the board we will do the testing. 

Your understanding and patience is greatly appreciated.

support team#2..."

Thinking about it out makes sense as the board is what delivers power to the screen..

Thanks for the update.
Sounds like I'll have to end up doing the same. My issue is persistent regardless of the cpu clock. As soon as I hit <=90% battery it begins on any brightness except brightness 0-2.