A thought about PTOD... (purple tint)

[NESnero]

I just had a thought about the PTOD.


When my Pandora wasn't infected with PTOD, sometimes I would find myself tilting the screen back quite far, putting pressure on the hinge. When I did this the screen would enter the same colourisation as if it had the purple tint of death, even though it didn't.


Well a while back, after my Pandora got PTOD, I did it again, this time however it had the opposite effect, and changed the screen colourisation back to normal, as if it never had PTOD, so it seems, if you view an already negative colour (or whatever colour change PTOD gives you) while already looking through that negative colour it'll change it back to normal?


So what I was thinking is, could you recreate the same colourisation effects with software as opposed to bending the screen back really far?


Something to mess or alter with the Pandora colours to maybe, reverse or alter the effects of PTOD? Something like wearing an extra pair of glasses to reverse the effects of the first pair.


I dunno, just a though. PTOD sucks.

 

[diligentcircle]

I'm not a hardware geek, but AFAIK, the PTOD is caused by connections being broken with one of the colors on the LCD cable or something (since it's a purple tint, that would be green). I suspect (unprofessionally) that what you're describing (having the hinge in a certain position) causes it to reconnect fully. In any case, it's a hardware problem, so it can't be solved with software.

 

[NESnero]

I see.


However, while I was playing a game on the Pandora, I hit the start button which brought up the pause menu. The actual level which was still visible behind the pause popup, was now darkened out a bit. The pause popup had the PTOD effects on it and had the wierd colouring, however the level which was now darkened out, seemed to have gone back to its normal colouring. I assume what happened was, when you bring up the pause menu, the actual level screen goes into a darker colouring, thus reversing the effects of the PTOD.


So put into simpler terms. I brought up the menu screen on a game with the normal PTOD effects. The game screen behind it darkened, and went back to normal (non PTOD) colouring.


If you skip to 0:36 on the video below you will see what I mean.

https://www.youtube.com/embed/hZN_gb7ic9k?feature=oembed

Because of this, I assumed it would be possible to simply change the colouring of the entire pandora screen through some software means. (contrast, balance, brightness, etc etc. I dunno I aint no expert)

 

[mcobit]

That won't work as color information is lost, when the cable is broken. You cannot increase the strenght of a color to reverse the effect, if this color is not displayable.

 

[NESnero]

and yet, I can clearly see my colouring revert back to normal when the whole Angry Birds screen darkening happens.... :wacko:

 

[mcobit]

That might be just because all colors go dark, what has the effect, that the missing colors don't seem to stick out that much and are not that obvious. But, well, why don't you play with color and brightnesssettings to recreate the effect?


Edit: Or maybe I don't get the point here... in this case: don't mind me

 

[NESnero]

I tried messing with the brightness and gamma settings, but nothing seems to work that well.


When the screen darkened in Angry birds, I swear the fudge, it went back to 100% normal colouring!!!

 

[Neelix]

As I understand it the LCD cable carries 8 data lines per colour channel so it could be that the darker colours aren't transmitting any data on the broken lines on yours. (Which makes sense if its only the lines for the most significant bits of the green channel that are broken.)


- Neelix

 

[WizardStan]

There are 8 or 5 lines per colour (not sure which, probably 5; doesn't matter, just know that there are multiple, and the more that are active the brighter the colour). When the PTOD starts happening, it is because one edge of the cable has been rubbing or twisting weird and has broken one of these lines. First to go is the brightest green line: by removing line 5 from the green channel, the colour brightness is reduced from 32 to 16 but still out of a possible 32: ie, the green becomes automatically darker and there's no way to brighten it. That's why darkening the screen causes the tint to go away, because that broken line is no longer being used.


If you really wanted to, it is possible to divide all colours by 2 such that the highest line is never used. The result will be a loss of colour information as everything becomes significantly darker, but at least there's no ptod.


Unfortunately, PTOD isn't a problem itself, it is a symptom of an ongoing problem, and just because you've "fixed" the colour temporarily doesn't mean the problem goes away. Ignore the ptod long enough and more lines start breaking: you'd have to remove more colour information, making it darker and darker. The backlight line also eventually breaks, and no messing with colours will do anything to help there.

 

[slaeshjag]

The LCD is 24bbp, so 8 lines per color

 

[NESnero]

If you really wanted to, it is possible to divide all colours by 2 such that the highest line is never used. The result will be a loss of colour information as everything becomes significantly darker, but at least there's no ptod.

How does one harness this power?

 

[Grench]

You are in denial.


You have early PTOD.


You need a new video cable.


That pretty much sums it up.

 

[FaeMinx]

I think what he really wants is to prolong the use of his Pandora before he's forced to send it away for RMA. So his question is both valid and useful for others suffering the onset of PTOD.


So how would one 'divide all colors by 2'?

 

[diligentcircle]

I think what he really wants is to prolong the use of his Pandora before he's forced to send it away for RMA. So his question is both valid and useful for others suffering the onset of PTOD.


So how would one 'divide all colors by 2'?

I'm guessing just turning down the contrast would do that. Don't know if that's possible on the Pandora, though.


I frankly have to agree with Grench, though. PTOD is a sign of a problem that (from my understanding) will only get worse. You should address the problem itself (get a new cable), not the symptom.

 

[urjaman]

Yeah, you'll (if my case is similar) first lose parts of green, then most of green, then red, then sync signals (picture spinning/total loss of picture)... Loss of blue, lcd power and touch screen is also propably possible. I think the speaker traces are a bit more robust, but anything carried by the cable can theoretically be lost. Also, adjusting the LCD contrast propably wont change the data that is carried on the cables, if it uses the LCD SPI based configuration (I'm not sure of this). (E: I'm waiting of ED to reply to my PM about selling me an LCD cable, but he is propably now a very busy man...)

 

[HuckFinn]

My Pandora suffered PTOD last year, May 8th, twas a sad day,


lasted until 3 weeks ago whereby the screen would be fine


if opened fully, then started getting tracking style lines


across screen and would have to press screen and wiggle


a bit to get the screen normal... now it's totally PTOD whatever


and also with lines unless screen is opened a bit, or if


I try to push the screen to the right.


Until a week ago I also encountered playing Shinobi on Mame,


that if I paused the game, the colours were darkened and you'd


swear PTOD was gone, as all colour info was there and correct,


albeit at half bright kinda mode.


Other symptoms were that until a week ago, once the


Pandora had been on a while, or was higher clocked,


running a game, then all of a sudden, without the screen moving,


the colours would suddenly go correct, and PTOD would dissapear.