This kind of symptoms indicated malfunction on the tack switch (AV/TV button key) and/or the microcontroller IC.
First thing to check is the tack switch, it must be sprayed by electrical contact cleaner or replace with new one to isolate it from fault. If the symptoms remain the same after a new replacement of tack switch, faulty microcontroller IC and its circuitry trigger this kind of symptoms. If this is the case, it needs to check and repair through the service center or by a qualified TV technician because the parts are surface mounted.
If you're unit is more than 1 year, standard warranty is already expired. Check if you've applied for an extended warranty of it.
If the unit is not under warranty period, I would advice you to seek for an assistance of a qualified technician to check the parts I've mentioned.
it needs service, that means using tools and meters and spare parts to find cause.
dead screen black screened at all times.?
even in HD TV antenna mode for HD TV?
or just the remote CLICKER batteries dead.
tell things that work and no not work , even LED actions.
the maker has no books on this old TV
https://jvcproducts.com/us/contact/support.html
here they are ask them>?
what rare TV. good luck fixing any RARE TV.
moved you to TELEVISION.
Return it to your place of purchase and get something else anything else you wouldn't believe how many people are having Issues with the LT series get rid of it.
Fault to the main power supply regulator section. Either it will be a separate board, or the part of main board. Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts.
http://electro-medical.blogspot.com/
It will be best to replace the power supply regulator board as card basis rather than making "Surgery" to it; which usually will make loss for both money and time. Even though you can make it right, it will cost around an amount equal to the cost of a new board; including the cost of (spare parts + service charge)
As a first step , if it is controlled via the remote, check that the remote batteries are good and that it is functioning ok. Does the tv show anything att all? If it does come on but shows nothing then it might be that the source selection is on the wrong kind of source, you can find on the remote whether this is so by going to the source menu which should probably be on digital. (I am assuming that you only have digital broadcasts where you are.
If there is no picture whatsoever ubplug the set and check whether the internal fuse(s) are ok.)