I picked up a dead Toshiba 42HL167 HDTV a while back and have tinkered with it off and on.
When I turn it on, the backlights kick on, a second later the picture appears, then it goes completely dark. Then a second or two later the backlights kick back on again, then after another second the picture appears, then dark again, and it stays dark.
At first I thought it was just a backlight failure, but now I'm realizing that it isn't just the backlights. When the screen goes dark it is also no longer sending a picture signal to the panel. I verified this by sending a very bright image to it and checking with a flashlight. Nothing. Totally black. Plus, when the backlight cycles the second time, the picture isn't there immediately.
When it has gone dark I can still switch inputs. That doesn't trigger the screen to come back on but if I hit the input button a few times and power cycle the TV I can see it has switched to another input when the screen flashes on briefly.
I updated the firmware with no effect.
Voltages out of the power supply are within spec. All the caps are Nichicon and none appear to be bulged out.
My thought is the main board has failed (seine board as I've seen it called, Toshiba pe0361), and the picture flashing is just a symptom of that. That board does control both the LCD itself and the backlights. One of the connections from that board to the primary inverter board goes to 3V when the backlight turns on, then drops to 0 when the backlights kick off. I've been tempted to jumper that wire to another 3V source to see if the backlights then stay on or not.
Before I go spend upwards of $80 on a replacement used board I wanted to see if you experts had any other ideas first, or whether this is even worth doing on this TV as it may be prone to repeat failure.
When I turn it on, the backlights kick on, a second later the picture appears, then it goes completely dark. Then a second or two later the backlights kick back on again, then after another second the picture appears, then dark again, and it stays dark.
At first I thought it was just a backlight failure, but now I'm realizing that it isn't just the backlights. When the screen goes dark it is also no longer sending a picture signal to the panel. I verified this by sending a very bright image to it and checking with a flashlight. Nothing. Totally black. Plus, when the backlight cycles the second time, the picture isn't there immediately.
When it has gone dark I can still switch inputs. That doesn't trigger the screen to come back on but if I hit the input button a few times and power cycle the TV I can see it has switched to another input when the screen flashes on briefly.
I updated the firmware with no effect.
Voltages out of the power supply are within spec. All the caps are Nichicon and none appear to be bulged out.
My thought is the main board has failed (seine board as I've seen it called, Toshiba pe0361), and the picture flashing is just a symptom of that. That board does control both the LCD itself and the backlights. One of the connections from that board to the primary inverter board goes to 3V when the backlight turns on, then drops to 0 when the backlights kick off. I've been tempted to jumper that wire to another 3V source to see if the backlights then stay on or not.
Before I go spend upwards of $80 on a replacement used board I wanted to see if you experts had any other ideas first, or whether this is even worth doing on this TV as it may be prone to repeat failure.
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