I'm trying to fix my 21 inch JVC TV, its on standby mode i detected the problem it was Horizontal output transistor, when i replace it with new one it work but after 24 days it got shorted again so i replace it again but this time when i switch it on the CRT just blink and then standby mode again and the HOT is shorted again, please help me what should check and do to fix my TV thank you very much.

Depending on circuit design in some TVs when flyback becomes defective then (1) only flyback gets deffective or (2) flyback & 1 transistor big in size fixed near flyback gets deffective or (3) flyback,big transistor & resistor or diodes or some times ICs will get deffective ..........so flyback replacement is compulsory + which ever components gets deffective ....... usually flyback gets deffective after 4yrs (between 4yrs to 12 yrs depending on TV brand & usuage ) .............so in your case along with horizontal transistor replace flyback also ..................... Remove that flyback from main board ? using marker make a mark (1 dot on knob & at the same line put another dot on flyback --- these 2 dots should be in same line ) on all the knobs on fly back ....now turn all the knobs one by one in anticlockwise direction slowly until it stops .... Then observe from the mark which you made before turning .. --- you will get an idea which knob howmuch it was turned in anticlockwise direction.... now take flyback to electronic shop & buy same type ( equivalent will not work )......at the shop itself check part number , number of pins & their position of old flyback with that of new flyback ----- everything should match 100% - nothing less nothing more .... it should be exact .... check many shops...now turn all the knobs of new flyback in anticlockwise direction very very very slowly until it stops....now fix it to mainboard very slowly & carefully....don't forget to connect red wire from flyback to TV TUBE ...again iam repeating don't forget to connect red wire from flyback to TV TUBE .... Now observe mainboard carefully whether any connector is not connected ....now connect only tv powercord & stay at a distance & switch on Tv for 2 seconds & then switch of immediately....during this 2 seconds TV gets on & led also gets on continuosly (won't blink) & there should not be any smoke or sounds on main board ...this confirms you have replaced flyback without disturbing other components & not shorted any joints..... so now again switch on tv ..wait 3 or 4 seconds ...led will be on but there won't be any picture ... Don't worry ....in the beginning you have observed howmuch knobs on your old flyback were turned in anticlockwise direction....remember..? see your old flyback again.... Now using suitable screew driver turn all the knobs on new flyback in clockwise direction one by one very very very slowly ...untill as it was in old flyback ( approximately ) --- remember TV is in on condition ... means high voltage will be there ... bymistake if you touch any part of the tv .. you will get very severe shock.... So be very very very carefull ..now while doing this adjustment observe what is happening on the screen - how brightness is changing ... Now switch off tv....connect signal ( antenna or dvd or cable..) & again switch on TV ....so now depending on brightness & clarity of the picture ..looking at the tv screen again you have to turn 1 or all the knobs on flyback either in clockwise direction or in anticlockwise direction very very very slowly ..once you start doing this adjustment practically then automatically you will come to know which knob should be turned . in which direction - & howmuch it has to be turned .... But remember this adjustment is very important .. Sometimes it will take 30mins to finalise the exact position.of knobs .. so take your owntime & finalise the exact position of those knobs..then switch off tv ..fix back the tv cover .. then switch on tv again ....that's all .......100% GUARANTEE again your tv will work normally ....