If you wish to get some details; visit the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/
faults & possible causes to LCD & Plasma screen are given with illustrations. You can get an idea about the fault to an extent. Faults to all LCD & Plasma screen are similar,
The coaxial cable coming from the dish goes to the input port of the set top box, take A/V (Y:video,R: Audio, W: Audio) cable to connect between tv and set top box.
Hope this helps, also check the manual which cabe with the set top box.
Without seeing the lines in question, it is difficult to say 100%. But, if the panel was cracked, the only remedy is to replace the panel. Given its age (3 months), unless there is specific evidence of impact, I would suggest that the crack may have come from the frame moving with time. Don't waste your time with the local shop. Call JVC directly and indicate that you had no impact on the TV and that the "shop" is trying to not repair it. Verify that the TV has the same problem as when you brought it to the shop.
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.)