yellowish tint on lg 42lg50-ug 42" and weird noise from the speakers.

Hi,

With the audio have you checked if the noise problem also occurs when using external sound systems connected to the RCA analogue audio out connections or the digital optical and coax audio out connections on the back of the TV?

Does the noise also occur when using different signal input types i.e. HDMI, Component video+ audio, antenna or even different signal sources e.g. antenna or a “box” of some sort i.e. cable box, media streaming device, dvd player etc?

If trying with external sound systems remember to alter the TV speaker setting in Menu > Audio > TV Speaker to Off as this disconnects the TV speakers and connects the audio to the external audio outputs

If the problem is in the TV and is not the source of the signal then here’s a link to the service manual that may help.

From p.18 onwards, you will find all the various audio troubleshooting flowcharts which may help you to isolate the problem and fix it.

With the yellowing screen, I think that the TV has inverter boards so this would suggest CCFL tubes in lieu of LEDs as you suspected, although maybe not as some of the earlier TVs had inverter boards to drive the LEDs, so it could either be an ageing tube (if it is CCFL) or perhaps a problem with one of the inverter boards. Maybe check the capacitors on the boards for any signs of leakage or bulging ends perhaps.

Hopefully a start.