Hello,
I've recently started having a go at repairing some TV's, and had some success but only had the pleasure of working on LCD types. I'm more used to laptop and PC repairs to be honest so this is a bit new to me. Anyway, I've never attempted repairing a plasma before but I've done a fair bit of research on here and think I've got the very basic gist of how they work and what the components/boards inside do... anyway enough gabble, now onto the problem:
At first, the TV clicked on/off all the time. Sounded to me like a short. I eventually found 4 shorted transistors on the Y-SUS board. I ordered a Y-SUS board on ebay since the parts to repair worked out just as much. Also I followed the LG training manual to test the Y-BUFFER for shorts (none found). However, since I'm a bit of a newbie and it appears common for Y-BUFFERS to fail after a bad Y-SUS and kill a new Y-SUS - I changed that too.
After installing a new Y-SUS and Y-BUFFER, the TV turns on! Finally! BUT, now there's more trouble. The bottom 3rd of the picture is white (not a perfect solid white bar, but more of a fuzzy horizontal white mess). There is no colour or movement on the screen at all (except for a bit of really high frequency flicker). The remainder of the screen is black. I've not dared to leave the TV on for more than a few seconds because it appears that the humming noise from the sustain boards gets a bit more high pitched and I didn't want to risk the Y-SUS frying if the original cause is still lurking on another board. I'll post a picture in the morning when I can.
If I disconnect the Z-SUSTAIN, I get the usual purple, slow update symptom but still no sign of an image (I figured worth a try, just wanted to see if I get any movement on the screen).
I also tried jumping the AUTO_GEN on the control board, but still nothing.
Incidentally I put the old Y-BUFFER back and that made no difference, so at least my little bit of troubleshooting on the buffer worked out right, there was nothing wrong with that!
I'm really eager to learn, and would be grateful if anyone with some expertise might be able to point me in the right direction of what to start checking. Since there's no sign of an image feed or colours, and AUTO_GEN does bugger all I did wonder if this might point to a control board fault... but it's just an educated guess. Then again, when the Z-SUS is disconnected there is some purple on the screen so I don't know. I have noticed that the control board led blinks.
Many thanks,
James.
I've recently started having a go at repairing some TV's, and had some success but only had the pleasure of working on LCD types. I'm more used to laptop and PC repairs to be honest so this is a bit new to me. Anyway, I've never attempted repairing a plasma before but I've done a fair bit of research on here and think I've got the very basic gist of how they work and what the components/boards inside do... anyway enough gabble, now onto the problem:
At first, the TV clicked on/off all the time. Sounded to me like a short. I eventually found 4 shorted transistors on the Y-SUS board. I ordered a Y-SUS board on ebay since the parts to repair worked out just as much. Also I followed the LG training manual to test the Y-BUFFER for shorts (none found). However, since I'm a bit of a newbie and it appears common for Y-BUFFERS to fail after a bad Y-SUS and kill a new Y-SUS - I changed that too.
After installing a new Y-SUS and Y-BUFFER, the TV turns on! Finally! BUT, now there's more trouble. The bottom 3rd of the picture is white (not a perfect solid white bar, but more of a fuzzy horizontal white mess). There is no colour or movement on the screen at all (except for a bit of really high frequency flicker). The remainder of the screen is black. I've not dared to leave the TV on for more than a few seconds because it appears that the humming noise from the sustain boards gets a bit more high pitched and I didn't want to risk the Y-SUS frying if the original cause is still lurking on another board. I'll post a picture in the morning when I can.
If I disconnect the Z-SUSTAIN, I get the usual purple, slow update symptom but still no sign of an image (I figured worth a try, just wanted to see if I get any movement on the screen).
I also tried jumping the AUTO_GEN on the control board, but still nothing.
Incidentally I put the old Y-BUFFER back and that made no difference, so at least my little bit of troubleshooting on the buffer worked out right, there was nothing wrong with that!
I'm really eager to learn, and would be grateful if anyone with some expertise might be able to point me in the right direction of what to start checking. Since there's no sign of an image feed or colours, and AUTO_GEN does bugger all I did wonder if this might point to a control board fault... but it's just an educated guess. Then again, when the Z-SUS is disconnected there is some purple on the screen so I don't know. I have noticed that the control board led blinks.
Many thanks,
James.
thank you helped me
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