lg 50ps3000 red haze

[caryg]

I'm trying to repair one of these LG plasmas which suddenly came up with the dreaded red haze - the picture has a red tint on most settings, apart from cinema when it is all green. Received wisdom seems to be that this is a fault with the high power transistors on the Z-SUS board, and that a kit like this one on ebay has all the bits needed to fix it.

Now I don't like just buying random parts without actually knowing if they are faulty, so a closer inspection of the photo of the bits and the board itself, plus a bit of searching led me to believe that what is being replaced are the bits I've circled red in the photo attached, namely one big 5W 10 ohm resistor, two 2.2 ohm 3W resistors, one large 1R0 surface mount resistor and a diode beside it (both a bit hard to see in the dark area above the heat sink, along with three power mosfets Q13, Q14 and Q15. Q13 and Q14 are both STP20NF20 200V 18A which can apparently give off 110 Watts (presumably when heatsinked properly), while Q15 is a FDP51N25 250V 51A which costs £2.15 a piece at RSS (plus 20% VAT), but has to be ordered in quantities of five, so that kit doesn't seem to be too bad value after all. There also seem to be 8 s/m 33uf 25v capacitors included, and I've no idea where they go.

And I'm glad I checked because all the above seem to be OK on my board. The resistors are spot on, the diode shows a proper diode drop, and the mosfets have no shorts. But while it's a good thing that I didn't waste my money, that sadly means that the fault is elsewhere and I'm not quite sure where to look next. Does anyone have any ideas?

[dam]

Re: lg 50ps3000 red haze

hi all,
i have exactly the same issue as caryg, can someone confirm if the components he has circled in his picture are indeed the components to replace, with the zsus repair kit? i apologize if this has been answered some where else, but ive spent hours looking for help with this, i have ordered the repair kit and my son is going to attempt to replace the components, we just need to be sure we are changing the correct bits..

please help, cant afford a new board, so a diy repair is our only option...

thanx

[speedypro]

Re: lg 50ps3000 red haze

Me too. Need to know if those are the parts need replacing.

[Furcot]

Re: lg 50ps3000 red haze

I have repaired the zsus fault for a customer using a kit of MOSFETS and power resistors etc from ebay for around £18 (this kit also contained a number of electrolytics requiring replacement on the processor card). After this the TV worked perfectly for around two months, but the fault has re appeared, again with the same failed (dead short) MOSFETS on the zsus board. I used heatsink compound and ensured the devices were tightly bolted to the heatsinks, so I think there must be an underlying cause - any ideas anyone

[tn245]

Re: lg 50ps3000 red haze

I think I remember tom66 mentioning in another thread that there's a theory the control board caps have something to do with the zsus going faulty.

I just recently repaired one of these with the zsus fault. I went for the ebay repair kit as it worked out about the same price as buying separately and I wasn't sure on the zener diode rating.

The caps that came with the kit were some cheap huahong ones. I used them at first and the kit did fix the main issue but I noticed there were still some problems with the picture - kind of dirty/speckly, especially in plain green areas. I then decided to replace those caps again using some quality panasonics and the picture seems as it should be now. I have the TV in an unheated room and I think the cold may have helped highlight the issue.