Check the pincushion diodes and the related passive components in the output
stage.

If you can, drive test and ring test the flyback. Also, look at the
collector waveform as you start it up and if it doesn't go directly to a
clean pulse with no ringing, you likely have a bad flyback.

These sets have had bad flybacks and problems in the pin circuits that will
blow outputs.

Leonard

"Max" wrote in message
...
James Sweet wrote:
"Max" wrote in message
...

Hi I trying to fix Sony KV-27FS12 27' TV.Front LED blinking 4 times.I
found short horizontal output transistor D2578.After replaced and try to
turn on TV the transistor blow out again after it start working for few
seconds.There is no bad solder connections on the board.I suspect bad
flyback.Any suggestions?Thanks



First thing I'd check are electrolytic capacitors, Sony sets that are
blowing parts can be a real pain to fix, they're good units but very
touchy
in some respects and have to be fixed just right.


I checked the caps which is involve in B+ line.All good.The TV start doing
HV but for few seconds then Horizontal output transistor blow out and TV
shut down to safe mode.I checked HV by HV meter connected to anode.Any
other suggestions.

PS TO TOM I'm a shop working in this business for 15 years.Fixed previous
models of Sony for 5 minutes especially when 2 blowed out transistor in
power supply and in chain reaction of blowed HO transistor.I never had the
problem like this with Sony that's why asking people who got similar
problem before to safe some time on troubleshooting.