LG 50PG20 plasma no power issue

[vinceroger69]

Re: LG 50PG20 plasma no power issue

i can see two one just below the two large capacitors (its a white fuse with silver ends) and the other bottom left of board by the red/blue mains wire connector.

[zell66]

Re: LG 50PG20 plasma no power issue

fuse F101 main fuse is good 0.2
308v fuse F801 does not read anything.

[zell66]

Re: LG 50PG20 plasma no power issue

fuse F101 main fuse is good 0.2
308v fuse F801 does not read anything.

[tom66]

Re: LG 50PG20 plasma no power issue

That would be a problem then. Check all the devices along the small long heatsink in the middle of the power supply board. I would take a guess a MOSFET or switching IC is shorted.

[zell66]

Re: LG 50PG20 plasma no power issue

Check all the devices along the small long heatsink in the middle of the power supply board. I would take a guess a MOSFET or switching IC is shorted.

sorry you realy lost me there. I have no idea what a MOSFET or switching IC is??

[tom66]

Re: LG 50PG20 plasma no power issue

You can see devices mounted to that heatsink, right?

Check them for shorts. Typically, they are MOSFETs (3 legged devices.) You do not need to remove them from the board to do the test.

To test for shorts, use the same mode on your meter that you used for fuses. Except this time, a reading of near zero is bad. Test all three combinations of pins (pins 1-2, 2-3 and 3-1) the polarity does not matter for a quick check like this.

If you find a device with more than 3 legs on that heatsink, please advise the part number printed on it so we can indicate where to test.

[zell66]

Re: LG 50PG20 plasma no power issue

ok thank you for that explanation!!

on most I am getting 0 but on some when it registers 0 it flashes 125 or 65 first then 0.

going from left to right on power supply board the second heat sink (?) registers 0 or close to 0.

the middle one registers all above 0

[tom66]

Re: LG 50PG20 plasma no power issue

Ok, would you read off the part number of each of those devices so I can check if those readings make sense. It will be printed on the front of it, maybe quite faint so use a light if necessary.

[zell66]

Re: LG 50PG20 plasma no power issue

sd20ng(or 6)0
grs749

this is the only on I can read with out removing parts.

this number is printed on the left face of the center 3 prong devise on heat sink #2 or second from right

[tom66]

Re: LG 50PG20 plasma no power issue

They are probably SD20N60
http://images.mcmanager.co.uk/ebayfi...-SD20N60-1.jpg

You would need to replace both of these, and the driver IC responsible for them.

Or the entire power board.

[zell66]

Re: LG 50PG20 plasma no power issue

would it be easier to just replace the entire bored? If so is there a specific board I need to look for on ebay?

[zell66]

Re: LG 50PG20 plasma no power issue

or do I buy a power supply component kit and resolder the devices to the board

[tom66]

Re: LG 50PG20 plasma no power issue

If you have never done surface mount repair before, the best option would be a board replacement.

[zell66]

Re: LG 50PG20 plasma no power issue

it has been many years since i have done sodering but I can give it a try.

http://www.ebay.com/itm/LG-EAY413609...item3a9ab98d62

[tom66]

Re: LG 50PG20 plasma no power issue

Looks mostly through hole, should be fairly easy.

[zell66]

Re: LG 50PG20 plasma no power issue

ok that ebay link i send you. is this the type of parts I need?

[tom66]

Re: LG 50PG20 plasma no power issue

They don't list exactly what is included so I wouldn't be able to say.

[zell66]

Re: LG 50PG20 plasma no power issue

I had a TV repair place look over board and agreed with me, 1 bad fuse and D603 on heatsink #2 is bad. Finding fuse is no problem, D603 is harder to find.

fcf20b0 i think is part number

[zell66]

Re: LG 50PG20 plasma no power issue

this is the part i cant find, marked as d603

[zell66]

Re: LG 50PG20 plasma no power issue

in the picture it is the middle one with a triangle peg pattern.