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-   -   Samsung plasma issue (http://www.videokarma.org/showthread.php?t=270519)

Boobtubeman 06-03-2018 04:42 PM

Samsung plasma issue
 
2 Attachment(s)
30-35 minutes into running, it develops this blue dot pixelation shadows over light scenes.
If i use menus, youll see the ghost of them in blue pixels after the menu is exited...

My camera has a hard time showing them, but hopefully, you can get an idea from the pictures i tried to take..

Obviously somethings getting warm, but what? is this a typical issue with this model??

Thanks... :)

SR

Boobtubeman 06-03-2018 10:07 PM

I should add this is a full screen incident, its not isolated to the top or bottom.. Only way i could describe it is as blue snow in patches of scenes depending on the brightness of the scene, otherwise all other aspects of the picture is acceptable, its just annoying blue snow. Text and screen images seem to be working fine..

MadMan 06-03-2018 10:57 PM

It looks like a loose connection to me. Good luck finding it. Could be a cracked solder joint or dirty plug on one of the boards. The telltale is that it happens when it warms up. Gets warm, metal expands, loses connection.

Boobtubeman 06-03-2018 11:49 PM

1 Attachment(s)
Yeah i was afraid of that.....:sigh:

SR

andy 06-03-2018 11:57 PM

...

mbates14 06-04-2018 08:01 PM

your symptom is known as Maldischarge. its caused by drifting sustain voltages.

The main power supply creates two main voltages, Vs, and Va. VS is the sustain voltage, and Va is the addressing/buffer voltage.

However, the Y sustain board has a plethora of DC-DC converters that generate various other voltages for each state during the charge/discharge cycle. like -Vy, Vsc, etc...

These can drift around or have ripple from drying out/bad caps and do this.

Hell, I have seen some plasma TVs (I own one) that the DC-DC converters have gotten so bad, that they cycle. tick tick tick causing the picture to pulsate bright/dim/bright/dim where the picture goes into full brightness/perfect, and quickly fades to a screen full of maldischarge to almost an inverted image, and cycles back again. Like a strobe light. All from bad caps.

Boobtubeman 06-04-2018 10:56 PM

I found a video online describing a similar problem and the guy traced it to 3 bad caps on the y sustain board. Looks like im going on a cap hunt....

SR

mbates14 06-05-2018 04:21 PM

Thats what I thought.

Older TVs I may have some knowledge gaps, but this modern stuff I know inside and out.


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