Hi Folks,
I have a powersupply inside a Samsung LCD monitor that turns itself off without fail after 20 minutes. All the Switchmode DC rail voltages such as 12V, 5V and 3.3volts all completely disappear. When you disconnect the mains for about 5 minutes and then plug it in again the power LCD monitor goes for another 20 minutes before completely losing it's power i.e. No Green power LED and no Picture. Even disconnected the load from the power supply, but it still has the same symptons. Sprayed Rapid Freeze on all the components, but it did make the power supply come back on- Even changed some Electrolytic caps due to higher than normal ESR readings but these have still made no difference. If you leave the power supply in standby mode with the green led flashing, it will stay on indefinately for days without losing the 5V DC rail. So if there are some Switchmode power supply experts out there, it would be nice to get a tip to solve this strange peculiar problem.
Kind regards
Paul Bellett