LG 452 Monitor

Thread Starter

tonydix

Joined May 4, 2010
27
This monitor will not start. On application of power the power led and all the other front panel leds light up briefly for about 1 sec. They then turn off and about 2 secs later they light up again. This cycling continues indefinitely.
The Mofset in the smps has been removed and checks out ok.
Careful visual inspection shows no obvious damage. I suspect SMPS shutdown due to another fault condition. No schematic available !
Any ideas would be most welcome
Thanks
Tony
 

Thread Starter

tonydix

Joined May 4, 2010
27
Any ideas about how to proceed would be much appreciated. Scope signals on various pins of the smps transformer indicate a square wave with some pins showing a dc jump in voltage in sequence with the flashing leds. A similar jump in voltage is detected on the main smothing capacitor after the diode bridge Without a schematic I am unable to work out what protection circuits exist on this chassis
Thanks
Tony
 
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