Author Topic: P10 Panel issue with FPP - green "echo"  (Read 333 times)

Offline lithgowlights

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P10 Panel issue with FPP - green "echo"
« on: January 12, 2019, 03:26:29 AM »
An odd issue was noted last year with my P10 panels running off a BBB and Octoscroller, where with plain text I was seeing the odd green pixel come on very faintly. Nobody ever saw the issue so I put up with it, but now it's time to work out what the issue could be. Swapping to completely new hardware, a Pi and RPi-P10 I am still seeing the issue on my panels, so I swapped out to different panels and they are showing the same issue.

This happens in both bridge mode when driven from xLights as well as the test mode from within FPP itself, so here are a couple of videos showing the issue. Oh I'm running 2.6 in this video, but it's been seen in 2.1 and 2.5.3 as well

From xlights with single pixel illuminated in a chase:

https://www.youtube.com/watch?v=TJfJfgwVjMc

Attached is also an image where I had the panel brightness down to 10% so the illuminated pixels dont "hide" the effect. Numbers 1 and 5 are white, 2 is red and you can see a very slight issue there, 3 is green and the issue is obvious, 4 is blue and there are a few small issues with other pixels on, but I cant say I have noticed the red and blue by eye, but you can see something on the camera.  Cables were also swapped today to see if there was an issue, but nothing changed




Direct from FPP showing the issue. Phone battery went flat at the end of the video, sorry :)

https://www.youtube.com/watch?v=z1zSNat2fvo


Offline lithgowlights

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Re: P10 Panel issue with FPP - green "echo"
« Reply #1 on: January 12, 2019, 03:27:36 AM »
Forgot the attachment

Offline Babybear

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Re: P10 Panel issue with FPP - green "echo"
« Reply #2 on: January 12, 2019, 04:50:19 AM »
Just off the wall what voltage are you running. Try a little lower.
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Offline lithgowlights

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Re: P10 Panel issue with FPP - green "echo"
« Reply #3 on: January 12, 2019, 04:56:00 AM »
5.07v at the input to the Pi and screens

Online dkulp

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Re: P10 Panel issue with FPP - green "echo"
« Reply #4 on: January 12, 2019, 07:03:49 AM »
5.07v at the input to the Pi and screens


Drop that to about 4.8 or 4.9.   My P5 panels had more than a faint echo when run at a full 5V.   Dropping them to 4.8 made it entirely go away.

Dan Kulp

Offline lithgowlights

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Re: P10 Panel issue with FPP - green "echo"
« Reply #5 on: January 12, 2019, 02:45:20 PM »
Dropped them right down to 4.2V (at the panels as measured by a Fluke Multimeter) and still the same echo, but it may have been very slightly reduced, but not by much at all.

Offline Poporacer

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Re: P10 Panel issue with FPP - green "echo"
« Reply #6 on: January 12, 2019, 07:47:42 PM »
You can try changing your Gamma to 2.2. That worked for me.
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Offline lithgowlights

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Re: P10 Panel issue with FPP - green "echo"
« Reply #7 on: January 13, 2019, 06:00:03 AM »
2.2 gives more realistic colors to the LED's that are on, but these seem to be turned on when they should be off, and gamma does not affect them to any greatly noticeable amount. Yes it's worse when things are dimmed, and my BBB powered 5*5 P10 screen also has the same issue, but at normal viewing distances you would never notice it - the one I posted earlier has a minimum viewing distance of about 5 feet, so it's a little more obvious

Offline David_AVD

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Re: P10 Panel issue with FPP - green "echo"
« Reply #8 on: January 13, 2019, 01:38:08 PM »
Is it worth trying the same panels with a HC-1 controller to see if the issue is with the BBB+Octo drive ?
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Offline lithgowlights

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Re: P10 Panel issue with FPP - green "echo"
« Reply #9 on: January 13, 2019, 03:06:31 PM »
Not a bad idea David, I'll try and get one. It happens with the BBB/Octoscroller and the Pi with one of Alans RPi-P10 hats as well, so it's either the panels or FPP that is the cause.

Online dkulp

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Re: P10 Panel issue with FPP - green "echo"
« Reply #10 on: January 13, 2019, 03:09:51 PM »



With the BBB, can you try setting the color depth to "7 bit zero lowest" and see if that helps at all?  Not a great solution, but I'm curious if that fixes it. 

Offline lithgowlights

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Re: P10 Panel issue with FPP - green "echo"
« Reply #11 on: January 14, 2019, 03:24:38 PM »
I tried 6, 7 and 8 bit on the Pi and 7 on the BBB with no appreciable change in the echo that I could see

Online dkulp

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Re: P10 Panel issue with FPP - green "echo"
« Reply #12 on: January 14, 2019, 03:50:20 PM »



No.. with 2.6 there should be a specific "7 bit, zero lowest" setting that I'm interested in.   It's still 8 bit, but always sets the lowest bit to 8.   I've seen some panels that seem to need everything set to zeros before switching rows.  I just haven't updated the PRU code to fully do that yet and this is a kind of work around for that.   

Offline tbone321

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Re: P10 Panel issue with FPP - green "echo"
« Reply #13 on: January 14, 2019, 03:53:20 PM »
Could this have something to do with the refresh rate on these panels?


Online dkulp

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Re: P10 Panel issue with FPP - green "echo"
« Reply #14 on: January 14, 2019, 04:01:12 PM »
Could this have something to do with the refresh rate on these panels?


Yes...   It seems like over the last couple years, more and more panel vendors are trying to figure out how cheap they can make these things and are finding cheaper and cheaper parts to put into them.   That includes shift register/buffer chips that cannot handle higher clock speeds, chips less usable at 5v, etc...




 

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