Replacement Y board came today, fitted and all faults gone.
Another one saved from landfill!
Thanks
Jim
bbjunkie
Badcaps Veteran
Last Activity: 03-18-2022, 03:10 AM
Joined: 12-14-2011
Location: N.W. UK
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Re: LG 50PS3000 noisy picture
Replacement Y board came today, fitted and all faults gone.
Another one saved from landfill!
Thanks
Jim -
Re: LG 50PS3000 noisy picture
Replacement Y sus board arrived today, the problem is gone. However the board is faulty as now I have no top half to the picture with some horizontal lines
Bottom half is absolutely perfect. Tried re-seating the ribbon cable which made no difference. Top half of picture works with other board, both are same part number & revision.
Getting there! Raised a dispute with eBay seller
Jim...Leave a comment:
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Re: LG 50PS3000 noisy picture
Using a method recommended by Tom66 in a different thread, (as shown [URL="https://youtu.be/51SZsfH60EY"]here[/URL]) I Removed Y buffers and checked for shorts, no input pins shorted to output pins.
In addition, after running for 10+ minutes, all heatsinks on buffers and other boards are warm but not hot to the touch.Re: LG 50PS3000 noisy picture
Using a method recommended by Tom66 in a different thread, (as shown [URL="https://youtu.be/51SZsfH60EY"]here[/URL]) I Removed Y buffers and checked for shorts,Leave a comment:
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Re: LG 50PS3000 noisy picture
Yes, the image is exactly the same with both boards. Without AUTO_GEN, and with the main board connected, I can see text in that solarised/noisy bottom part of the screen from a game console that was connected before I got the TV. Is this significant?
I'm sure I saw someone on the forum have a similar failure mode but can't find the post now.
I've tried removing the ribbon cables from the top Y buffer board one at a time, this didn't make any difference other than leaving a black bar across the screen.
...Leave a comment:
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Re: LG 50PS3000 noisy picture
Should VS voltage have a fluctuating AC component? Was checking rails for ripple, VS appears to be swinging wildly while measuring on AC, it's showing a stable 194v DC though.Leave a comment:
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Re: LG 50PS3000 noisy picture
Yes, I removed the flat flex cable to the main board and bridged the 1st two pins on the control board plug P6 (labelled AUTO_GEN) with one end of a clip-lead....Leave a comment:
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Re: LG 50PS3000 noisy picture
Ok, that explains the low reading! Can confirm correct ZBIAS getting 104.3v there.
So despite the control board being a rare failure and the second showing the same fault you think I should try ordering another?
TIA
JimLeave a comment:
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Re: LG 50PS3000 noisy picture
Plug I'm referring to is bottom left, P100
...Leave a comment:
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Re: LG 50PS3000 noisy picture
Decided instead of getting caps to get a replacement control board from eBay as it was just as cheap and less hassle, the fault is exactly the same. Thing is, the board could've been faulty. Also how coincidental would it be that the replacement board has exactly the same issue (noise on the picture and the horizontal bar at the bottom of the screen)
Perhaps I should try ordering another control board.
Before I do,
ZBIAS measured at the plug on the Z board was 5v not 105v - am I...Leave a comment:
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Re: LG 50PS3000 noisy picture
Great, thanks
- I'll try replacing the caps ( see others mentioning a common issue of faulty 100uF 25v caps on the control board) if that doesn't work i'll try to find a board.
Leave a comment:
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Re: LG 50PS3000 noisy picture
No reference to the Zbias voltage on panel, ...Leave a comment:
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Re: LG 50PS3000 noisy picture
AUTO_GEN test is still showing the flickering, tried to capture it on video but it's not showing up very well, in addition to this there was an odd horizontal bar during part of the test. [URL="https://www.youtube.com/watch?v=q-kMPFlBwTc"]link to AUTO_GEN video here[/URL]
Checked some voltages while I was there;
Y sus
M5V = 5.06v
VA = 60v
VS = 194v
-VS = 194v (should this be negative WRT to ground? - double checked its definitley not)
Z sus
+15v = 18v
CTRL_OE...Leave a comment:
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LG 50PS3000 noisy picture
Not sure how you would describe this, the picture appears like there is noise getting onto the video - horizontal lines and flickers.
[URL="https://youtu.be/fuxAn_6Uig0"]Video Here[/URL]
Any thoughts where to start?
thx
JimNot sure how you would describe this, the picture appears like there is noise getting onto the video - horizontal lines and flickers.
[URL="https://youtu.be/fuxAn_6Uig0"]Video Here[/URL]
Any thoughts where to start?
thx
JimNot sure how -
Re: LG 50PS6000 intermittent problem (Video included)
@mods need to remove the video link, it's a spam link to a pron site
Oh well, back to finding a fix for my 50PS6000
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LG 42PX5D-EB buffer temps
A while back I repaired a LG 42PX5D-EB which had a bad y-sus board.
Recently I have just obtained an IR thermometer which I thought would be an excellent tool to check the buffer board for suspect chips.
All but one of the chips are running around 25c (21c above ambient in my cold workshop) the other is running around 9c
Do these chips tend to run quite warm or could this be a sign of a failure which could blow the new (reclaimed) y-sus board?
Cheers for now
Jim -
Re: LG 42PX5D-EB dead
Swapped back to old buffer board and picture returned. Assume this was a faulty item(thankfully the ebayer refunded me)
Will try to find another.Leave a comment:
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Re: LG 42PX5D-EB dead
Spent another evening at the LG last night, removed the board and re-seated the ribbons. Didn't make any difference.
Will try swapping the buffer board back to the old one.
/jimLeave a comment:
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Re: LG 42PX5D-EB dead
Hi again!
Finally got more time to look at this, turns out the cable plugs in underneath the lower PCB on another board.
I have just sourced a buffer board and replaced it due to the original getting a bit hot. Now I have nothing but sparklies.
Is this a board problem or do I need to adjust the tv to suit the new buffer board? (pic was perfect on old board, just a couple of the chips were getting hotter than the others)
Cheers for now
/bbj...Leave a comment:
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Re: LG 42PX5D-EB dead
Thanks tom66, all ok it seems. However am having trouble remembering where one of the cables goes. There are two cables that look like they are shielded data cables, one goes from the logic board to the very left hand side (marked in green) The other one marked in red, I cant find where it plugs in, one end goes on the logic board, the other - I cant remember! I stripped this set down in early 2012 so cant recall was it even plugged into anything.
The photo attached is the original I took in Jan. 2012 with arrows pointing to where the cables...Leave a comment:
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Re: LG 42PX5D-EB dead
Hi guys, never did post a follow up to this.. mainly because the set isn't fixed yet! Got a secondhand y-sus board from an online supplier of plasma and LCD spares. Just about to power it up on my next visit to the workshop (it was buried under a ton of other stuff hence taking so long!). Is there any way to protect my new board in case one or both of the buffers is shot ?
Cheers
JimLast edited by bbjunkie; 06-01-2014, 02:59 PM.Leave a comment:
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