panasonic tx-48ax630b trouble

[alerton]

hi guys im back again.

i got this tx-48ax630b panasonic that i thought had backlight issues but its something else.

the tv powers on green led flashing for a split second when all the backlights flash on just for a second then goes off and red led flashes 1 time continuously. i checked all the backlights and double checked again and seemed ok but i took the screen off anyway just to make sure and every led is fine.

very occasionally when it is unplugged and powered back on the tv will stay on but 99% of the time its just as described. what advice is there and what should i be looking for please?

[alerton]

Re: panasonic tx-48ax630b trouble

i have found and downloaded the service manual if that would help any of you clever people to pin point the problem

[R_J]

Re: panasonic tx-48ax630b trouble

1 blink is BL_SOS, How did you check the backlights? How can you be sure every led is fine?
There are 7 return lines from the panel led's, check the voltage on each return line while turning on the tv, I suspect one or more lines will be different

[alerton]

Re: panasonic tx-48ax630b trouble

1 blink is BL_SOS, How did you check the backlights? How can you be sure every led is fine?
There are 7 return lines from the panel led's, check the voltage on each return line while turning on the tv, I suspect one or more lines will be different

i started with checking with a led tester and all the lines seemed ok but i still wasnt convinced so i have taken he lcd off and checked each led strip individually and all are drawing the same voltage and every led is working.

i tried checking the voltages on the power supply but the time between switching the tv on and it going into fault mode is literally a split second so dont have time to get a reading.

[alerton]

Re: panasonic tx-48ax630b trouble

ok so i finally had time to mess with this a bit more and eventually found 1 led that was working but drawing way more power than the others causing the bl_sos. sooooo...... now i got the tv working but it has some narrow horizontal black lines on the screen starting darker from the right and going to just over half way across the screen and fading to invisible by the time they get to the left side of the screen. there are about 10 - 12 randomly spaced lines, hard to get a photo but you can just about make out the lines. i have checked all the connections and tried flexing / moving all the ribbons which makes no difference, so has anyone any idea what might be causing the lines? to be fair i never seen the tv working before i got it so it might be that the lines were there even before i got it. thanks everyone for the help etc etc.

[alerton]

Re: panasonic tx-48ax630b trouble

1 blink is BL_SOS, How did you check the backlights? How can you be sure every led is fine?
There are 7 return lines from the panel led's, check the voltage on each return line while turning on the tv, I suspect one or more lines will be different

you were quite right, i eventually found 1 bad led that was lighting fine but drawing too much power and causing the bl_sos. the tv is now working again though it does have some lines on the screen that may have been there before i even got the tv or maybe as a result of damage from getting into the pannel (bloody thing was glued together and fought a good fight to stay glued together lol) but anyway thanks for the advice and just though i should let you know that you was correct.