Sounds like something has caused a short in the HV circuit. Not sure how old your JVC tv is but it looks like your picture tube will have to be replaced which could be costly. It could also be that transistor has went out on your CRT board which is also a costly replacement unless you know how to do it yourself. It would be cheaper just to replace the JVC tv at this point unless you have a warranty.
Tv bought 18.02.11 but I did not get an extended warranty. Thanks for your reply.
TV bought 18.02.11 but I did not get an extended warranty.