Advent HD TV - loud ringing - won't turn on

[PMNILSEN]

I have an advent hd tv and when i plug it in it just has a high pitched ring and the tv wont turn on. Horizontal output transistor possible problem or something else?

 

[davenn]

I have an advent hd tv and when i plug it in it just has a high pitched ring and the tv wont turn on. Horizontal output transistor possible problem or something else?

I would be checking the switchmode PSU initially. if its possible to disconnect it from the
cct it supplies (ie its plug/cabled to the rest of the electronics on a separate board)
do so and check voltages present. look carefully on the circuit board/s for screen printing
that indicates what voltages are to be found at various testpoints etc

Assuming the TV has been working ok for some time prior to this failure ....
if its a ~ year or so old looking at all electrolytic capacitors especially in the PSU see if
any are starting to bulge even only slightly .... pretty obvious on the top of them.
Replace any that are bulging .... they WILL be faulty make sure you use the same
rated values and paying attention to using 105 C hi temperature caps

Over and over again I replace faulty (cooked) electros in PSU of all sorts of modern gear
They just dont get enough ventilation and overheat.
I have LCD computer monitors in for repair that are failing after only 6 months of use

cheers
Dave
VK2TDN