Hi All.
I do not ask many Technical questions here. I can normally work out stuff myself. I should be able to after so many years with CRT otherwise I would be considered useless
.
Anyway, lately we are getting Secondary Diode failures. Specifically on the 12V rail on the TV....
Replace the offender...and it goes shorted again because it is running too hot.
Set comes in. Customer reports dead set. Dead indeed. Normal procedure. PSU fine et al. Won't go into all details here. I believe this is a specific TV CRT SMPS problem..
OK...I have had all kinds of failures on the Secondary side from LOPTX arcing over and damaging Regulation so set trips and all. I have seen it all. I thought....All there were associated with the LOPTX and B+ and so on. You know Line running and all....
This MF is different. Picture is perfect. Sound is perfect. TV is looking and sounding 100%. But it insists of taking the 12V rail and destroying the poor Secondary Diode......
So, I soldered Copper cooling fins on the Diode....It got through the day and all is good so far.
Another Three days of soak testing needed. I don't like my solution though. I need to know why.
Any clued up person here that can maybe provide answers ?
As always
tvtech