pandora erratic behavior (flickering screen / hangs)


b_o_b

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One of my Pandora's has the following problem

Flickering screen (random, not PTOD) then sometimes hangs - black screen (but does not go off). Touch screen is sometimes unresponsive.
Already reinstalled firmware. Battery is fully charged, issue is similar on minimenu and xfce.
 
This Pandora has a history of erratic behavior I already sent it a couple of times for repair to ED. It seemed to work fine for a short while after the last repair (not sure how long because I don't use this Pandora much)

Still think the root cause (I assume hardware) hasn't been solved.

Does anyone recognize this? Is there a program to test the hardware?
 
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Maybe the famous coil that is loose? You could try to open the ubit and see if it is still in place and the solderjoints are good.


Edit: When the screen goes black, is there nothing on it or is it just the backlight that fails?


Can you get it to work again by pressing together the lowrr casepart firmly?
 
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Maybe the famous coil that is loose? You could try to open the ubit and see if it is still in place and the solderjoints are good.
Just checked the wiki and it says that dropping the pandora can cause this. Before the last repair I indeed dropped it pretty hard, so might be something to look into.

Edit: When the screen goes black, is there nothing on it or is it just the backlight that fails?


Can you get it to work again by pressing together the lowrr casepart firmly?
Nothing on it, but the LCD screen is still emitting light (only screen is black)

Just tried a game of squared and it was flickering a lot, pushing the lower case doesn't seem to help but it does appear to affect the flickering a bit.

One other thing I noticed is that the game is dropping in speed (to 0) and then after some flickering animation speeds up again and continues. In some cases it goes black and then returns to the game again.

Seems that the longer the pandora is activated the worse it becomes (heating up?).
 
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Might be a defect lcdcable or indeed some cold solderjoint or something. But ED might have more insight info.
 
Yeah, as my LCD cable goes I started with colour resolution losses, then v-sync started to go so I got jumping, and occasionally it just gives up and leaves the backlight on, but I can fix that by opening and closing the lid a few times, so I've not got round to doing anything about it yet.

But apart from those visual issues, and my outstanding issue with USB host after a few enable/disables, my Pandora is rock solid.  If the LCD cable is going here, I think there's some other fault at play too.
 
But apart from those visual issues, and my outstanding issue with USB host after a few enable/disables, my Pandora is rock solid.  If the LCD cable is going here, I think there's some other fault at play too.
I doubt it has anything to do with the LCD cable. I once had a POTD so I should be able to recognize that problem and it seems unlikely that a similar cable issue affects speed. I personally suspect one of the components on the mainboard. Hopefully ED can shed some light on this issue.
 
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Maybe the famous coil that is loose?
Opened my Pandora and there doesn't seem to be anything loose - pushed the coil and other objects on the board but everything seems firmly attached. Attached a picture of the board, sorry for the bad quality.,  

Behaviour is now pretty consistent. After a cold boot (not playing with it for >24 hours) it works fine for a few minutes, but then the problems start with flickering / hanging and automatic rebooting. Test program squared. 

p_inner.jpg
 
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It's rebooting as well? Battery alignment is the usual culprit when it does that in isolation, but as it's also hanging and causing visual artifacts, and it only seems to happen when the system is warm, I suspect a dry joint somewhere.


Your photo is a little blurry, but I think it says that board is a rev. 3a. I think my Ghz unit has a rev 5 board (although I haven't had it open recently - I might be getting mixed up with the LCD cable revision), so I suspect yours is a CC unit - is that right?
 
It's rebooting as well? Battery alignment is the usual culprit when it does that in isolation, but as it's also hanging and causing visual artifacts, and it only seems to happen when the system is warm, I suspect a dry joint somewhere.


Your photo is a little blurry, but I think it says that board is a rev. 3a. I think my Ghz unit has a rev 5 board (although I haven't had it open recently - I might be getting mixed up with the LCD cable revision), so I suspect yours is a CC unit - is that right?
Yes it is a CC unit. I doubt the battery has anything to do with it. I have also played it while continiously pressing the back, same thing happened. It also happens if I just let it stand and not touch it at all. Pressing the back while it is flickering does seem to do something though (makes it worse or temporarily better), so indeed a dry joint / bad connection on the board could very well be the root cause. 
 
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