21PT4443/94R NO PICTURE AND SOUND REMOTE COMMANDS OK

there is no picture and sound. remote command are woreking , can be changed to standby and operate by remote(LED indication). SMPS is OK , %V is OK. Horizontal driver pulses with scope are OK on the primary sideof driver transformer(coil). Horizontal transistor is also OK. Initially problem used to come after few hours of operation and then period reduced to 3 to 4 hours and then few minutes and now it does not start at all.