Re: Samsung Plasma Intermittent Vertical Bars (repeatable) PN50B430
Yea seems like it is. Bummer, i feel like that built in pixel fix program in the menu did it in by driving the screen too hard for its age/state. I swear it was working fine at moderate brightness untill that test shorted something and it started getting the black bar more and more easily.
Live and learn
JesusJones
Member
Last Activity: 02-19-2023, 02:09 PM
Joined: 05-05-2015
Location: MB
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Re: Samsung Plasma Intermittent Vertical Bars (repeatable) PN50B430
I'll add that the center photo shows more of the early failure signs (starting to fuzz out, pretty far gone already in that photo) and the right photo shows its just about to fully fail and go solid black.Leave a comment:
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Re: Samsung Plasma Intermittent Vertical Bars (repeatable) PN50B430
The tv was not impressed by my demands for photos. Seemed worse than ever.
I noticed and remembered some more info that might matter. The panel looked like it had mild burn in (horizontal spans at top and bottom of screen 3-4" wide each) with more of a yellow hue than the rest of the picture.
When a black, blank, image is displayed the panel turns off (pitch black). If you bring a mouse pointer onto the screen from the left or right it will relight the panel (as if a backlight turned...Leave a comment:
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Samsung Plasma Intermittent Vertical Bars (repeatable) PN50B430
Trash picked this plasma for parts and found it had some bad solder joints. It powered on after reworking most of the boards and seems like it may even work.
The symptoms is, when showing a picture of bright (mostly white) intensity (within the affected area only) a vertical strip 2 3/4" wide will begin to fuzz out (just to the right of samsung logo, 16 3/8" from screen edge), and soon turns black (from top to bottom). Changing to a darker scene immediatley ater will cause the black stripe to fade back in (it fuzzes and clears up again) and it starts working just fine.... -
Re: LG-42d69u no 24v output from smps E59670
The line sensing pin gets 1.69v and the 1M resistors test good. C827 also tests well, right at 22nf and no DC leakage up to my testing limit of ~100v. C828 also tested good in the same way.Leave a comment:
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Re: LG-42d69u no 24v output from smps E59670
Had some time and I may have narrowed it down more. Noticed that there is a PFC_stop pin that goes low when the IC shuts down. According to the IC schematic this is controlled by an OR gate with three inputs. Two of those inputs are from disabled features that are not used in this design leaving only the overcurrent (Isen) pin to be tripping the shutdown. Using a multimeter on the Isen pin never shows a voltage near high enough to trip the OCP. But that is just slow multimeter...
Applied 24v to the output of the supply...Leave a comment:
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Re: LG-42d69u no 24v output from smps E59670
I have confirmed that:
ps_on recieves 3.23v consistently when the power is turned on. AND The PWM IC (MOSFET switcher) does not shut down. It outputs the 2v reference from the Rfmin pin with the mosfets removed and the inverter board disconnected. Presence of the 2v signal is what I'm using to confirm it has not latched off.Leave a comment:
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Re: LG-42d69u no 24v output from smps E59670
Sorry, I jumped the gun a bit with my answer. I will try connecting the supply with MOSFETS removed and report back.
Previously with supply voltage (400v) removed from the mosfets the MOSFET switchign IC would not shut down.Leave a comment:
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Re: LG-42d69u no 24v output from smps E59670
Previously, without the inverter connected the 24v supply still did not come up. The PFC (makes the 400v right?) would stay working. Just the mosfet switching IC for the transformer primary latches itself off. It still receives Vcc power and everything it would have when running normaly (as far as I can tell) it just aborts start up and becomes latched off and needs a reset to try again.Leave a comment:
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Re: LG-42d69u no 24v output from smps E59670
The mosfets and heatsink are currently out. Hence the empty space above the transformer....Leave a comment:
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LG-42d69u no 24v output from smps E59670
Hello
I picked up one of these tv's in uknown condition and have found that everything seems to be working except the 24v supply which powers backlights and audio. The 3.3 and 5 and 12v rails and stdby, ps and backlight ON signals are present when cycling the TV/supply. The 24v section can be heard trying to start, but just wont power on and gives no output (.07v). I have no experience troubleshooting SMPS and have learned a fair bit already but am now stumped on what to try or do next.
So far:
I have found that the electrolytic caps (sus'con HG, MG, SG non bloated... -
Re: New Members - please post your introductions here
Hey, seems like to good place to gain experience and knowledge in the hobby.
Cheers!Leave a comment:
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