Haier Televison & Video - Page 6 - Recent Questions, Troubleshooting & Support

You'll have to get that from the manufacturer of the remote, not from Haier. Every universal remote uses its own coding system.

The TV should have a "Variable Audio" out port.

If your audio circuits have gone South then you have an issue with your main board of the set or the amps that power the speakers. See if you have audio voltage at audio output on set. If so issue is with amps and you can always connect your audio receiver to that output and get sound like that. I blew an amp and that is what I have been doing without any sweat.

Sorry but that is not a thing that is adjustable.

If you wish to get some details; visit the site linked here. Pull up older posts. http://electronicshelponline.blogspot.com/

Sounds like the power supply board is going out on it. I'm a t.v. repairman and many times, I just replace the capacitors on the power supply board and they work great. If you aren't qualified do not attempt this yourself. High voltage will kill. Not worth it, take it into a shop.

what year is it?

Two probable points; either the loss of the service voltage for the high voltage section or a failure in that section.
The circuit that produces the high voltage for electron beam acceleration also produces the sweep for the horizontal movement of the beam, in other words, if this circuit fails or the voltage it needs to operate is gone, no picture, but the audio still functions.
Because of its Chinese origins, there is a chance that critical specialized parts may still be available for it or, if you are lucky to have a tech competent to repair standard TVs, he may find a less critical part that has failed and readily available.