Hey everyone I am a new member here. I came across your forum while investigating what happened to my LG Plasma TV. It seemed that 3 out of 4 hits came back to you here @ BadCaps.net so I figured I would try to tap some of the knowledge and expertise I see from the members here. I actually became interested in electronics as a hobby a few years ago as I work on electrical panels/switchboards and I went to school for computers...this seemed to bridge some gaps in my knowledge. I am however basically a self taught newbie here. 
and I need lots of help at the moment figuring out where to start on this disaster.
OK. To begin my LG50PG20-UA plasma TV's picture suddenly went out while watching TV the other day. The power light and sound still work. No menu, or input picture of any kind (black screen). After investigating this a bit I found that power supply, fuses, or the y sus board where my likely candidates for common failure. I took the back panel off and proceeded to check all of the fuses on the PS, y sus, and z sus. They all looked good even the smaller "micro" fuses I found the boards all checked out.
Next I checked the voltages going into the y and z sus boards. I got 193V, 59V, and 5.0V. Again the power supply to both seemed to be ok. I checked for visual damage to caps or burns on the topside only of the board (did not remove) and I did not see any. I then let the unit run for 15 or 20 min. Mostly to see if it was getting hot (or staying cold). I did not notice a marked change in the temperature of the heat sinks on the y sus or y buffer boards. One of the heat sinks on the z sus board was not as warm as the others but warmer than room temp.
At this time or around then I noted voltage on the y buffers leaving to the TV ribbon cable at about 52V. The voltage to the ribbons off the x sus was about 78V. This is when disaster or my own idiocy
got the better of me. I decided to check the voltages on the transistors on the cooler heat sink on the z sus board. I was having trouble getting a reading on one when I accidently shorted the base and an emitter together. This blew the main fuse on the z sus board. Who knows what else? Oh boy...what did I do here? Where to start fixing this mess.
So my uneducated guess is that the y sus was the problem originally, but I wanted to further check it because finding the part (new $220) was not as easy as I thought (out of stock) or affordable. Plus I couldn't find visual proof of it being burnt and didn't know its correct output value to the y buffer either or other test procedures. After I shorted out the z sus board the voltage to the y buffer dropped to 14 or 15v. I don't know if the y sus finally gave out more or if it is a symptom of frying out the z sus? The input voltage to both boards from the supply still checks out ok.
So can I fix the x sus with a new fuse? The leads (on transistor) did not melt but did arc a bit before fuse burnt up. I know the fuse is bad. Can I test the transistor etc? I am not an expert solderer, but I do have one and could do a fuse repair (soldered in there) maybe 1 transistor not a bunch etc. I'm still learning here, and a bit timid after my mistake here.
So whats your advice from here guys? I made things harder on my self for sure.
Unfortunately, I cant afford to pay someone else to fix it....So its going to have to be a DIY job and waiting on parts etc. is going to be half the fun! Not to mention dealing with a rookie unsure repair man LOL. Yeah! Thanks a lot for any help offered in advance. I may need it
and I need lots of help at the moment figuring out where to start on this disaster. OK. To begin my LG50PG20-UA plasma TV's picture suddenly went out while watching TV the other day. The power light and sound still work. No menu, or input picture of any kind (black screen). After investigating this a bit I found that power supply, fuses, or the y sus board where my likely candidates for common failure. I took the back panel off and proceeded to check all of the fuses on the PS, y sus, and z sus. They all looked good even the smaller "micro" fuses I found the boards all checked out.
Next I checked the voltages going into the y and z sus boards. I got 193V, 59V, and 5.0V. Again the power supply to both seemed to be ok. I checked for visual damage to caps or burns on the topside only of the board (did not remove) and I did not see any. I then let the unit run for 15 or 20 min. Mostly to see if it was getting hot (or staying cold). I did not notice a marked change in the temperature of the heat sinks on the y sus or y buffer boards. One of the heat sinks on the z sus board was not as warm as the others but warmer than room temp.
At this time or around then I noted voltage on the y buffers leaving to the TV ribbon cable at about 52V. The voltage to the ribbons off the x sus was about 78V. This is when disaster or my own idiocy
got the better of me. I decided to check the voltages on the transistors on the cooler heat sink on the z sus board. I was having trouble getting a reading on one when I accidently shorted the base and an emitter together. This blew the main fuse on the z sus board. Who knows what else? Oh boy...what did I do here? Where to start fixing this mess. So my uneducated guess is that the y sus was the problem originally, but I wanted to further check it because finding the part (new $220) was not as easy as I thought (out of stock) or affordable. Plus I couldn't find visual proof of it being burnt and didn't know its correct output value to the y buffer either or other test procedures. After I shorted out the z sus board the voltage to the y buffer dropped to 14 or 15v. I don't know if the y sus finally gave out more or if it is a symptom of frying out the z sus? The input voltage to both boards from the supply still checks out ok.
So can I fix the x sus with a new fuse? The leads (on transistor) did not melt but did arc a bit before fuse burnt up. I know the fuse is bad. Can I test the transistor etc? I am not an expert solderer, but I do have one and could do a fuse repair (soldered in there) maybe 1 transistor not a bunch etc. I'm still learning here, and a bit timid after my mistake here.
So whats your advice from here guys? I made things harder on my self for sure. Unfortunately, I cant afford to pay someone else to fix it....So its going to have to be a DIY job and waiting on parts etc. is going to be half the fun! Not to mention dealing with a rookie unsure repair man LOL. Yeah! Thanks a lot for any help offered in advance. I may need it
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