I have a 4 yr old Sony Bravia KDL-52W5100 that has no picture or sound after powering on. The tv has never given us any trouble until the last few months. During that time it has this intermittent problem that shows up as “frozen” controls when trying to use the remote, then a few seconds later the tv loses volume while displaying a picture, and a few seconds after that the tv shuts off by itself, then immediately turns back on. Then everything would be fine again. It would then repeat this problem, sometimes an hour later, or several hours, or days, or even several days. Very intermittent. Then a couple of weeks ago, there were a couple of instances of the tv just losing signal (like disconnecting the coax cable). When that happened, we turned it off, waited a few seconds, turned it on, and it was ok. Also within the last few weeks, there were a couple of instances of partial video output, with bad horizontal lines across the picture. Again, shutting of the tv, waiting a few seconds, then turning it back on eliminated the problem.
Finally, a couple of days ago, I turned on the tv, the Sony logo lit up, and the green “power-on” light came on, but there was absolutely no picture or sound. Trying to change volume, channels, inputs, etc, either on the tv or with the remote doesn't do anything. Turning the tv on and off doesn't fix the problem. So I unplugged it for a day, while I started researching the issue on the web. I'm a newbie here, and never have worked on a tv, but have repaired printers, and computers so I am confident enough to try to fix this.
My research led me to try the following. First I took the back off the tv so I could access the inside components. When I plug in the tv, it “clicks”. I can turn on the tv with either the tv power button, or the remote control. The tv attempts to power on normally (Sony logo below the screen lights up) and the green “power-on” button lights up, and stays on as constant green, but that is all. There is no sound or picture, and there are no red error lights, or blinking codes.
Looking inside the tv with the power on, none of the back lights light up. The power supply board (G7N) gets slightly warm, as does the Main Board (BU). Neither of the Inverter Boards (D3N or D4N), nor the TCON board, seem to get warm. First I examined all the components, looking for any evidence of leaks, overheating, etc. Nothing found. Next, I suspected the power supply, so I checked continuity of the main AC power fuse, and found it was fine. Next, I checked all output voltages from the power supply board using a voltmeter. All the 3.3, 12, and 15 volt outputs tested perfect to all the downstream boards…Inverters, TCON, BU.
Next, I pulled all the main connectors to the main boards, and reattached them. Then I tried the tv again. No change. Since all the output voltages checked out, I suspect the power supply (G7N) board is ok, so I started looking at the Main Board (BU). While the power was on, I pulled the CN6202 Connector off the power supply (G7N) board. This connector is on the ribbon cable that feeds the Main Board (BU). As soon as I pulled that connector, the tv “clicked” and shut off (green power button turned off). I then plugged the connector back in and the tv “clicked”, the green power-on button lights up, and within about 2 seconds, all the back lights come on, and stay on for about 20 seconds, then all the back lights shut off, but the green power-on button continues to light up. Still no picture or sound. Also, when the back lights come on for that brief 20 seconds, no picture or light is visible on the screen.
So this is my problem. Anyone have any ideas? Could this be a bad Main Board (BU)? If so, I have some questions about how to replace it. From looking at my board, and doing some research on the web, I am finding conflicting information as to whether or not BU boards with the same part numbers are really interchangeable. For example, one site I found said you can use the same BU board for the following tv's: KDL-52W5100, KDL-40W5100, KDL-46Z5100, KDL-52XBR9, KDL-46XBR9, and KDL-40XBR9. But ShopJimmy says KDL-52W5100 only swaps with KDL-52W5150. Other sites say it depends on the Serial Number of the tv. Does anyone know what is right? My Main Board (BU) has the following 2 part numbers: 1-879-224-14 BU, A-1671-683-A. And my tv serial number is 8015236. According to several web sources, the Sony Part Number for the BU board for the KDL-52W5100 is A-1734-658-A.
Sorry for the long post, but I wanted to make sure I covered everything I know about this problem. Any help from any of you experts out there would be much appreciated!
Finally, a couple of days ago, I turned on the tv, the Sony logo lit up, and the green “power-on” light came on, but there was absolutely no picture or sound. Trying to change volume, channels, inputs, etc, either on the tv or with the remote doesn't do anything. Turning the tv on and off doesn't fix the problem. So I unplugged it for a day, while I started researching the issue on the web. I'm a newbie here, and never have worked on a tv, but have repaired printers, and computers so I am confident enough to try to fix this.
My research led me to try the following. First I took the back off the tv so I could access the inside components. When I plug in the tv, it “clicks”. I can turn on the tv with either the tv power button, or the remote control. The tv attempts to power on normally (Sony logo below the screen lights up) and the green “power-on” button lights up, and stays on as constant green, but that is all. There is no sound or picture, and there are no red error lights, or blinking codes.
Looking inside the tv with the power on, none of the back lights light up. The power supply board (G7N) gets slightly warm, as does the Main Board (BU). Neither of the Inverter Boards (D3N or D4N), nor the TCON board, seem to get warm. First I examined all the components, looking for any evidence of leaks, overheating, etc. Nothing found. Next, I suspected the power supply, so I checked continuity of the main AC power fuse, and found it was fine. Next, I checked all output voltages from the power supply board using a voltmeter. All the 3.3, 12, and 15 volt outputs tested perfect to all the downstream boards…Inverters, TCON, BU.
Next, I pulled all the main connectors to the main boards, and reattached them. Then I tried the tv again. No change. Since all the output voltages checked out, I suspect the power supply (G7N) board is ok, so I started looking at the Main Board (BU). While the power was on, I pulled the CN6202 Connector off the power supply (G7N) board. This connector is on the ribbon cable that feeds the Main Board (BU). As soon as I pulled that connector, the tv “clicked” and shut off (green power button turned off). I then plugged the connector back in and the tv “clicked”, the green power-on button lights up, and within about 2 seconds, all the back lights come on, and stay on for about 20 seconds, then all the back lights shut off, but the green power-on button continues to light up. Still no picture or sound. Also, when the back lights come on for that brief 20 seconds, no picture or light is visible on the screen.
So this is my problem. Anyone have any ideas? Could this be a bad Main Board (BU)? If so, I have some questions about how to replace it. From looking at my board, and doing some research on the web, I am finding conflicting information as to whether or not BU boards with the same part numbers are really interchangeable. For example, one site I found said you can use the same BU board for the following tv's: KDL-52W5100, KDL-40W5100, KDL-46Z5100, KDL-52XBR9, KDL-46XBR9, and KDL-40XBR9. But ShopJimmy says KDL-52W5100 only swaps with KDL-52W5150. Other sites say it depends on the Serial Number of the tv. Does anyone know what is right? My Main Board (BU) has the following 2 part numbers: 1-879-224-14 BU, A-1671-683-A. And my tv serial number is 8015236. According to several web sources, the Sony Part Number for the BU board for the KDL-52W5100 is A-1734-658-A.
Sorry for the long post, but I wanted to make sure I covered everything I know about this problem. Any help from any of you experts out there would be much appreciated!
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