Update Regarding LG Plasma 42pq3000

[benfinland]

Thanks for all the help on here especially to Tom who has been helpful. My issue was the tv would click but not start. Having read stories of repair kits for power supplies I thoroughly tested the power supply board. No bulging caps or any burnt smells. Both large 22 OHM resistors ok, all diodes passing the diode test the only thing I didnt test any caps or transistors.

I found when measuring voltages on the power supply to the Y sustain board the 2 17 volt supplies and 1 5 volt supply were reading zero unless I unplugged the Y sus board where they appeared then as normal. There appears to be a short in the Y Sus board.

New Y sus board and adjusted the display and TV is perfect after months of being sat in the back room . I hope this is of some use to someone in the future.

Thanks guys,
Ben Finland

[benfinland]

Re: Update Regarding LG Plasma 42pq3000

One issue is that there is a 4 inch black horizontal line across the top of the screen now. TV picture is good just this line. I will bring my fluke meter from work tomorrow and adjust the voltages correctly according to the label info in the tv . But do you think the panel might have gone tits?

[capkid]

Re: Update Regarding LG Plasma 42pq3000

Check to make sure your Y-buffer connectors are all seated properly. It could be a bad buffer, also. Got a pic?

[benfinland]

Re: Update Regarding LG Plasma 42pq3000

Hi pal, thats what I thought do I opened the Y Sus buffer board connectors last night and removed the ribbons and reseated making sure they were straight all ok. I did push some of the Ysus connectors on the Y sus board now i have 1 black line 3 inched wide at the bottom as well as top. Its a £20 second hand board of Ebay same Rev number and part number. I`ll take a pic and upload it. Its perfectly watchable lol but id like to fix it its a good telly. Got some great black contrast now since i adjusted it So would hope to make perfect.

[tom66]

Re: Update Regarding LG Plasma 42pq3000

It's probably just a loose connector -- they're really difficult to get seated properly.

[benfinland]

Re: Update Regarding LG Plasma 42pq3000

Heres a pic of the screen with top n bottom horizontal black lines

[tom66]

Re: Update Regarding LG Plasma 42pq3000

OK, select a black source on the screen. In a dark room, do the faulty bars light up slightly with the rest of the panel, or are they pitch black?

[benfinland]

Re: Update Regarding LG Plasma 42pq3000

Hi Tom, I`ll have a look later on as the wife is watching without a trace and im a dead man if I dare interrupt it haha.

[benfinland]

Re: Update Regarding LG Plasma 42pq3000

It was a commercial break luckily, Lights off and the black bars are very black and rest of screen is lighter with a faint ghosting of the previous image which to be honest the tv always did that. So yes to confirm bars jet black more than watchable part of the screen

[tom66]

Re: Update Regarding LG Plasma 42pq3000

Good, that narrows the problem down. Will need to get the cover off when you're free so the problem can be looked at. LG plasmas do tend to have minor image retention, but it's rarely a problem.

[benfinland]

Re: Update Regarding LG Plasma 42pq3000

Superb That`s great Tom much appreciated. If your free tomorrow evening 4 pm or 5 pm your time I shall pop the back off.

[tom66]

Re: Update Regarding LG Plasma 42pq3000

Probably doing work then, but I'll see if I get time to check.

[benfinland]

Re: Update Regarding LG Plasma 42pq3000

Cheers Tom I`ll try you at 5 but can check back later.

[benfinland]

Re: Update Regarding LG Plasma 42pq3000

Hi tom couldnt make it today. Can you give me some pointers as to what to check and i can bring the Fluke meter home from work tomorrow? I think that its either the second hand Ysus or the buffer board hopefully not the screen. I shall have a look . By the way do you know if a repair kit exists for the ysus board? id like to fix this board. To be honest I havent even checked the fuse on it because I was so consumed initially assuming the power supply was the fault. It was only then that I realised that the loss of the 17 volt and 5 volt feeds to the y sus from the pspu were caused by a failure on the ysus board. Id like to fix this y sus and re install it to test it.

[tom66]

Re: Update Regarding LG Plasma 42pq3000

It is likely the buffer chip near the appropriate connector or connection on that part of the panel. Rarely the panel itself.

[benfinland]

Re: Update Regarding LG Plasma 42pq3000

Hi Tom, well got a week out of it now its well n truly gone tits. Now there is sound but screen has vertical yellow,pink spatters and no picture. Any clue as to the issue? Could the buffer board for the YSus gone south? Ive not even had the back off yet but I know one thing I didnt get round to setting the Voltages before it actually went tits. I am looking at fixing it again with second hand stuff and once ive got it nailed I can buy new LG parts to ensure a long life. Im thinking if I get it working of wiring a fan up to a thermal switch running off a 12 volt relay to keep it all cool as It gets quite warm . Is it worth trying to adjust the voltages to see if imakes a difference? Im thinking that there is an issue with that buffer board as I got the original lower horizontal black line with by fiddling with the ysus connectors. Remember its a second hand board, it does however have identical numbers and rev numbers etc. Regards, Ben

[tom66]

Re: Update Regarding LG Plasma 42pq3000

Can you post a picture? Definitely sounds like the buffer board has died a death completely.

A fan may help, but instead of a thermal switch run it on 7~8V using a resistor of around 22 to 33 ohms in series. This will work better than a fan kicking in and out.

Compare the voltages to the panel sticker, if they are incorrect adjust them. Consider dropping Vs by a few volts to improve panel efficiency.

[benfinland]

Re: Update Regarding LG Plasma 42pq3000

Good idea than having fans kicking in. Where is the best place to pick up a 12 volt feed? I will be able to work out current draw when I buy a fan to place an inline fuse holder between the source and the consumer. Yes I reckon its popped its clogs the old buffer board. I dont have the Fluke at home so will take back off tomorrow when I bring some tools home. Im gutted because I nearly purchased a Y Buffer board a month back but decided to just buy a second hand Y sus. I`ll open her up tomorrow. Cheers Tom. I really hope i can fix this permanently, because frankly its been a pile of crap as far as consumer electronics go. In my humble opinion LG stuff is diabolical and seems to have diabolical customer service also. Trouble is being 3000 miles from the UK things take ages to arrive. And to buy things here forget it, theyre normally 3 or 4 times the price.