Re: LG 50PG20-Ua blows mosfets and fuse

My mistake!! I stated that the 10amp fuse was blowing,but it's the 5amp fuse that keeps blowing.My fluke meter is capable of reading amperage, so I tried reading the amperage when one board was hooked up and then the other board. The highest reading I could get was 1.5 amps. When you add the 2 boards toghether it doesn't even use 4 amps, so why is it blowing a 5 amp fuse? Without a wiring schematic it's hard to say what all is running off that 5 amp fuse. Would anybody know where I could get a copy of the wiring schematic for this power supply?...

Re: LG 50PG20-Ua blows mosfets and fuse

The sticker on the back of the tv say Vs is 193v,and that is what I read on the Vs leads. All the voltages are what the sticker says they should be. Thanks for your responce!!

I am working on a few different LG tv's and would like to know if there is a way to enter the sevice mode when they won't power on,just blinking lights. I repaired a Sharp 60" and was able to enter the service screen by pressing the vol+ and the channel- then plugging the power cord in. I was wondering if LG has the same feature or not? I haven't been able to find anything like this yet. The tv's I'm working on are as follows; LG 60PA6550-UM,LG 60LS5750-UB, LG 50PC3D-UD,and LG 50PG20-UA. Any help would be greatfull.

Re: LG 50PG20-Ua blows mosfets and fuse

I tried a few of the tests for the Ysus board and the Zsus board,as far as voltages. I just had the Zsus board hooked up and the bias voltage was 89v and the label says 100v. I ajusted it up to 100v. I then diconected the Zsus board and conected the Ysus board. The Vy voltage was 197v and label says 195v,so I ajusted it to 195v. The Vsc voltage was what the label says it should be. Do you think that little amount of difference would make it blow the mosfets and fuse? I'll keep testing and reading.

Re: LG 50PG20-Ua blows mosfets and fuse

Thanks for the responce tw2005!! I have measured the voltages with one board or the other installed as well as without any boards installed. The voltages are the same no mater which way I try it. They are; Va 65,Vs 193 and 5V. I've been afraid to try both boards again,as I'm down to my last mosfets. The attachment you sent will no doubt help as far as troubleshooting goes. I will read it and try some of the tests. It appears to draw more power than the power supply can handle when both boards are hooked up. I just have to figure out what is...

I am a newbee to repairing plasma tv's.I have an Lg 50PG20-UA that i have been working on. When I first got it and removed the back noticed that a few caps were bad.I pulled the power supply and replaced the bad caps, 5amp and 10amp fuses. The last person to do any work on this set just soldered new fuses on top of the blown ones,so I replaced them the correct way. I also noticed that they had replaced a few other caps also. I just hope they replaced them with the correct sizes. After replacing the PS I plugged it in and powered it on. It turned on for a few seconds then shut down and wouldn't...

Re: LG 50PG20/UA Shuts off

Hi, This message is for FelixTheHouseFreak. I know this thread is over a yaer old,but thought I would try to contact Felix.I need the manual that you gave the link to. It appears you can't access this link anymore. If you have a PDF file of this manual,I would appriciate a copy. I have the same issue with my tv and it is the same model 50PG20-UA. I hope you had a Merry Christmas. Thanks, Buzz