I am a hobbyist (not a professional) so please be gentle...
I recently received an XR-77A80J that wouldn't turn on. (Repeating 5 flashes when plugged in.)
I did a hard reset by holding the power button for about 30 seconds until the set powered down. I then tried to turn it on and it powered up, bringing me to the setup screen. There's not a lot of detail on the setup screen but the picture didn't have any distortions, so at least a cursory examination suggests no physical damage to the screen. The set appeared to be working normally, but it shut down after about 15 seconds, this time repeating 4 flashes. I then unplugged it, plugged it in again, and I was back to 5 flashes.
Interestingly (to me at least), this appears to be completely repeatable. The TV will start up after a hard reset, will function normally for about 15 seconds, and then will shut down with 4 flashes.
I searched the forum and found some troubleshooting provided by Diah in another thread...
I disconnected the 2 black sockets on the TCON board (from the PSU) but that didn't stop the flashing, so I pulled the PSU, measured 3.51V on pin 6 of socket 6401, connected it (in order) to pins 5, 1 and 3, and read 12.85V on TCON_12V and 21.6V on EVDD. (I couldn't find the referenced sockets 501 and 601, so I measured the voltages from the pins of socket 6601.)
I don't know if I should be concerned with the fact that TCON_12V is a bit high, but I proceeded to the next step which was to leave pins 1, 3, 5 and 6 connected, unplug the cable from socket 6401 at the main board, disconnect both LVDS cables from the TCON board, and plug in the TV. I expected the screen to come on and show me something that might help me to determine if the problem was in the display, but the screen remained dark.
I then removed the jumpers, plugged in the LVDS cables and the cable to the main board, and the TV returned to its original condition (working normally after a hard reset for about 15 seconds).
I assume that I did something wrong in the TCON/panel test or something would have shown on the display. Did I leave something out? At this point I feel like I'm back at square one...
The power supply may be bad because it's putting out 12.85V rather than 12V on TCON_12V.
The main board could be erroneously shutting down the set.
The TCON board could be failing.
The panel could be drawing too much power.
I'm hoping that the fact that the TV consistently works for about 15 seconds after a hard reset might be a big clue to someone. (15 seconds seems like an awfully long time for a protection circuit to detect a failure.) I'm not in a position to buy a whole new set of boards, especially if the problem may be in the panel.
I would appreciate any insight you might be able to provide. FYI, there is no indication of physical damage to any of the boards or the display. Thanks!
I recently received an XR-77A80J that wouldn't turn on. (Repeating 5 flashes when plugged in.)
I did a hard reset by holding the power button for about 30 seconds until the set powered down. I then tried to turn it on and it powered up, bringing me to the setup screen. There's not a lot of detail on the setup screen but the picture didn't have any distortions, so at least a cursory examination suggests no physical damage to the screen. The set appeared to be working normally, but it shut down after about 15 seconds, this time repeating 4 flashes. I then unplugged it, plugged it in again, and I was back to 5 flashes.
Interestingly (to me at least), this appears to be completely repeatable. The TV will start up after a hard reset, will function normally for about 15 seconds, and then will shut down with 4 flashes.
I searched the forum and found some troubleshooting provided by Diah in another thread...
I disconnected the 2 black sockets on the TCON board (from the PSU) but that didn't stop the flashing, so I pulled the PSU, measured 3.51V on pin 6 of socket 6401, connected it (in order) to pins 5, 1 and 3, and read 12.85V on TCON_12V and 21.6V on EVDD. (I couldn't find the referenced sockets 501 and 601, so I measured the voltages from the pins of socket 6601.)
I don't know if I should be concerned with the fact that TCON_12V is a bit high, but I proceeded to the next step which was to leave pins 1, 3, 5 and 6 connected, unplug the cable from socket 6401 at the main board, disconnect both LVDS cables from the TCON board, and plug in the TV. I expected the screen to come on and show me something that might help me to determine if the problem was in the display, but the screen remained dark.
I then removed the jumpers, plugged in the LVDS cables and the cable to the main board, and the TV returned to its original condition (working normally after a hard reset for about 15 seconds).
I assume that I did something wrong in the TCON/panel test or something would have shown on the display. Did I leave something out? At this point I feel like I'm back at square one...
The power supply may be bad because it's putting out 12.85V rather than 12V on TCON_12V.
The main board could be erroneously shutting down the set.
The TCON board could be failing.
The panel could be drawing too much power.
I'm hoping that the fact that the TV consistently works for about 15 seconds after a hard reset might be a big clue to someone. (15 seconds seems like an awfully long time for a protection circuit to detect a failure.) I'm not in a position to buy a whole new set of boards, especially if the problem may be in the panel.
I would appreciate any insight you might be able to provide. FYI, there is no indication of physical damage to any of the boards or the display. Thanks!
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