Switching power supplies in cheap "throw away" TV's

[radiotvnut]

Has anyone ever run into a switching power supply in one of these cheap TV's that was kicking out wwwwaaaayyyy too much B+? I've got a 2004 13" Durabrand (don't laugh) that was given to me by the TV shop. I just thought I'd play with it just to see if I could get it going. When I got the TV, there was an open 2.2 ohm resistor from the filter cap to the raw B+ input of the switching transformer. After checking and not finding any shorted components, I fired the set up and got a sudden burst of HV and then it went dead. The HOT was found to be shorted and a safety resistor in the B+ line opened. Before going any further, I measured the B+ and it's running at a whopping 256 volts! These TV's usually run around 100 volts. I replaced the optocoupler and a 1 uf, 50 v lytic close to the switching transistors' heat sink. Still no change.

During this whole procedure, I'm asking myself "why in the hell didn't they stick to a simple IC voltage regulator system based on something like an STR30130. Those were common in '90's era TV's and the circuit was simple and easy to repair. And, you didn't have to worry about B+ going through the stratosphere!