I have a Pioneer Kuro KRL-37V LCD TV with a problem. It's about 12 years old and was used as our main TV for about 9 years, it's now
been moved to the guest appartment.
I decommisioned it because after 4-6 years, don't quite remember when exactly, the follwing issue started popping up:
When I power on the TV it initially works fine. As an example I plug in a chromecast and it will play
several hours before the problem begins: a single green pixel will appear on the screen and stay green/become stuck.
If I now switch the TV to a different input channel on which there is no signal,
a lot more pixels will turn green and over time their number steadily increases.
Pixels that become green will be stuck green until switching to a different source.
The build-up of green pixels goes much more rapidly on inactive hdmi inputs than on rgb.
If I now switch back to the hdmi source to which the chromecast is connected, it will also have many more green pixels.
The upper right hand corner of the screen (where the TV briefly superposes the selected input) is completely free of green pixels though.
The number of green pixels seems to no longer go up, but picture quality is not enjoyable anymore.
Also there now seem to be some blue or grey (hard to see, much lesser intensity) pixels.
If I pause the movie, switch to a different source and back, there is a different pattern of green/stuck pixels.
If the TV is turned off and left off for about 20 minutes this chain of events will repeat itself.
To me it suggested some kind of thermal issue. When I take the back cover off, it takes much longer for the problem to manifest itself.
I took the metal cover/heat sink off the LCD control board and noticed that the condition
of various thermal pads was questionable, so I replaced them all with a liberal amount of heat sink compound.
Had the TV running fine for a couple of hours with the back cover still off so I could measure the
temperature of the metal cover, and everything seemed just fine. Then put the cover back
on and let it run some more until it shut itself off and the red 'standby' led started blinking.
I can not find anything in the service manual as to what the specific blinking pattern means.
If I do a cold start of the TV the following will happen:
1) The blue 'on' led blinks 8 times then goes on.
2) The TV briefly displays the currently selected input channel in the right upper corner.
3) The display shuts off and the red 'standby' led starts blinking with about a one second interval and without any pause.
I have tried to get the TV in the adjustment process mode by hold “VOL (-)” and “INPUT” when turning it on
but I cannot get it to go in that mode.
Does anybody here have a clue what problem is indicated by the blinking of the leds?
been moved to the guest appartment.
I decommisioned it because after 4-6 years, don't quite remember when exactly, the follwing issue started popping up:
When I power on the TV it initially works fine. As an example I plug in a chromecast and it will play
several hours before the problem begins: a single green pixel will appear on the screen and stay green/become stuck.
If I now switch the TV to a different input channel on which there is no signal,
a lot more pixels will turn green and over time their number steadily increases.
Pixels that become green will be stuck green until switching to a different source.
The build-up of green pixels goes much more rapidly on inactive hdmi inputs than on rgb.
If I now switch back to the hdmi source to which the chromecast is connected, it will also have many more green pixels.
The upper right hand corner of the screen (where the TV briefly superposes the selected input) is completely free of green pixels though.
The number of green pixels seems to no longer go up, but picture quality is not enjoyable anymore.
Also there now seem to be some blue or grey (hard to see, much lesser intensity) pixels.
If I pause the movie, switch to a different source and back, there is a different pattern of green/stuck pixels.
If the TV is turned off and left off for about 20 minutes this chain of events will repeat itself.
To me it suggested some kind of thermal issue. When I take the back cover off, it takes much longer for the problem to manifest itself.
I took the metal cover/heat sink off the LCD control board and noticed that the condition
of various thermal pads was questionable, so I replaced them all with a liberal amount of heat sink compound.
Had the TV running fine for a couple of hours with the back cover still off so I could measure the
temperature of the metal cover, and everything seemed just fine. Then put the cover back
on and let it run some more until it shut itself off and the red 'standby' led started blinking.
I can not find anything in the service manual as to what the specific blinking pattern means.
If I do a cold start of the TV the following will happen:
1) The blue 'on' led blinks 8 times then goes on.
2) The TV briefly displays the currently selected input channel in the right upper corner.
3) The display shuts off and the red 'standby' led starts blinking with about a one second interval and without any pause.
I have tried to get the TV in the adjustment process mode by hold “VOL (-)” and “INPUT” when turning it on
but I cannot get it to go in that mode.
Does anybody here have a clue what problem is indicated by the blinking of the leds?
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