36" Panasonic dead.

[Dani]

CT-36HX40CB dead, horizontal output shorted, nothing else bad, replaced
it, now it starts up, but only momentarily, but shuts right down. All
B+ voltages come up, but go right back down. I got the service manual
from the Panasonic site, but there's no schematic. Has anyone repaired
one of these for this fault? Thanks, Dani.

 

[dennis]

I'm not familiar with this chassis, but it is probably a bad B+ regulator.
Usually in the neighborhood of 120-160vdc. May be an STK series IC.
This is a common failure mode. B+ voltages look good at startup, but rises
above regulated level and unit shuts down. You don't have time to see the
overvoltage before shutdown. I never figured out if the output transistor
shorting overloads the regulator or the regulator failing destroys the
output transistor, but it happens a lot.

 

[David Naylor]

I'm not familiar with this chassis, but it is probably a bad B+ regulator.
Usually in the neighborhood of 120-160vdc. May be an STK series IC.
This is a common failure mode. B+ voltages look good at startup, but rises
above regulated level and unit shuts down. You don't have time to see the
overvoltage before shutdown. I never figured out if the output transistor
shorting overloads the regulator or the regulator failing destroys the
output transistor, but it happens a lot.

Comon problem with this chaxic...replace the fly back