How can i use LA76931/5AM3 with LA 76931/5AP4 I had tried and the raster was perfect but the it goes in misfuction like channel goes up and volume +

Hi Stephen, yes, it is almost certain that the problem is in the function or control board, usually there is a surface capacitor (SMD) that goes into loss and causes these failures
Another possibility, would be the remote control, which works erratically, remove the remote control or keep it in a closed place and check if the fault continues
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Greetings Franco Dosil

Hola Stephen, si, es casi seguro que el problema esta en la placa de funciones o control, por lo general hay un capacitor de superficie (SMD) que entra en perdida y provoca estas fallas
Otra posibilidad, seria el control remoto, que funciona erratico, retira el control remoto o guardalo en un lugar cerrado y verifica si continua la falla
Comenta los resultados
Saludos Franco Dosil

First ensure that you are performing the auto channelling procedure correctly.

If you are sure you have done everything in the proper way, and channel tuning still does not work, than that means that the tuning board inside your TV is faulty, and is not storing channels in memory, therefore should be replaced.

Back - light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
http://electronicshelponline.blogspot.com/
Some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement.

If there is no video signal input, this kind of fault can occur. An abnormal "Screen" voltage too can be the cause. If video processor IC or the tuner is faulty, this kind of fault can occur too. You should check all this. If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. Do a search by type in the brand name of your device at its search box and press "Enter".
http://electronicshelponline.blogspot.com/

do you mean if you hooked up the tv with the aerial antenna can not get any channel? ok if just a white raster only and doesn't scan or tuned even manually and auto search, the cause is bad tuner.

Electrolytic capacitors are good at causing hum. You could try replacing some of them, they are not expensive. Otherwise you might have damaged the left channel amp semiconducter, whatever that might be.

Try and turn off the closed captioning. I had the same problem and it turned out that the closed captioning was on t1 instead of OFF. Hope this helps!!!!

Good Day;
If you have no video, has raster and sound Check I012, 3.3 Volt reg. Good Luck, big IRISH.

Tienes un problema con los push buttons en la carita uno de ellos esta danado.Resetea tu estereo en la carita tiene un mini orificio con un boton para resetearlo intenta esto,suerte.