LCD Refresh is visible


PowerGod

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I'm not sure if it's related to the last 1.52 firmware update, but the refresh lines on my Pandora are too visible, it's distracting even when searching an icon on the desktop...


How can I change the refresh rate ?
 
LCD shouldn't have refresh lines. Like, at all, the technology just doesn't work like that. Can you describe exactly what it is that you're seeing?
 
I'm guessing he's got tearing.

I had a look on the wiki page http://en.wikipedia.org/wiki/Screen_tearing and can be this, but I'm not so sure... I see (only after I focus them) horizontal lines at the same distance (~1 cm) from each others moving from the bottom to the top of the display, but seems like them are actually going from top to bottom so fast that seems them are moving in the opposite direction...


It's almost the same effect when you set the wrong refresh rate on a crt monitor, except for the fact that is not flickering... that's why I asked for refresh rate...
 
mmm... seems this happens everytime after I run Vice-x64


EDIT: ok, I'm 100% sure the cause is Vice-x64, the lines appears just a second after I press enter to start the program and then remains there after I close it.
 
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That's the 50Hz mode. All our LCDs do that.
 
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wuuut?


How does one activate this 50Hz mode? I'm trying to replicate the problem. I've tried Vice EX and it doesn't seem to do any weird scanline thing.
 
wuuut?
How does one activate this 50Hz mode? I'm trying to replicate the problem. I've tried Vice EX and it doesn't seem to do any weird scanline thing.

Vice EX doesn't do that, only the latest version from pickle.


It's needed for buttersmooth scrolling.


UAE4ALL does that as well, btw
 
I had set a vertical gradient from bright grey (#999999) to dark gray (#666666) as my XFCE desktop background image (a.k.a. wallpaper).

And in a later Pandora session I observed the seemingly same experience as @PowerGod:

Horizontal lines in very close succession (every 3mm or so) which alter the brightness of their underlaying content, and which move on the vertical axis (cannot recall wether up or down, movement from my memory about 0.5cm/sec).

I moved my Pandora within my room as I suspected electromagnetic interference, but that didn't change it.

Restarted, then the problem was gone!

I retroactively tried to determine the issue:

Besides:

1) a hardware problem, such as

a) shielding,

B) loose contact / pressure on cable through hinge,

c) ...? 

2) I more strongly suspected that a software left my Pandora in this state.

a) Could not remember which one it could have been. Had recently used: Giana's Return, PicoDrive with both NTSC 60hz and PAL 50hz games (suspicious!), maybe others as well or in parallel. Impossible to tell now. Tried them all. Could not evoke the problem.

B) Ran sudo /usr/pandora/scripts/op_lcdrate.sh with both the 50 and the 60 argument. Could not reproduce the issue either!
 
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Usually, those can be seen with 50Hz.

The LCD has some issues with that. You can see it clearly when playing Amiga games.

Probably an emulator or game you used didn't switch back from 50Hz to 60Hz, so you could see it on XFCE Background.
 
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My experience so far:

If you booted fresh, then switching 50/60 via op_lcdrate.sh does not trigger those strange scan lines!

But as soon as you once HAD the condition within a Pandora session, caused from whatever PND (i.e. PanPlayer), you can then reliably switch on/off the scanlines with op_lcdrate.sh [50 | 60]
 
My thoughts: Every LCD has some kind of inversion scheme. Its technically necessary.

Look here (http://www.lagom.nl/lcd-test/inversion.php) on your desktop monitor, depending the monitor, at least one of those patterns will flicker or show something scanline-alike (top to bottom, left to right or so). Its called pixel walk. Perhaps Pandoras inversion scheme changes with refresh rate..
 
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