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Equipment Repairs => LCD TV forum => Topic started by: high-tech on September 08, 2012,18:46:03

Title: Westinghouse SK-32H540S "2 seconds to black" Darfon
Post by: high-tech on September 08, 2012,18:46:03

I found an inverter transformer with open secondary and replaced with new, and the TV still shuts the backlight off after a couple seconds and it trys a second time but still no good. I checked the N channel mosfets feeding the primary side of the inverter transformers and they are good. I don't have a schematic for this board and wish I could find one... I also ohmed the other two inverter transformers secondary 1.8k ohms.
I used a set of test lamps and they all light up for 2 seconds and go off again so my bulbs are ok im pretty sure.
Im hoping somebody here knows this problem inside out

im getting the necessary voltages on the ps_on and bl_on pins on the power supply board connector

Title: Re: Westinghouse SK-32H540S "2 seconds to black" Darfon
Post by: watteau on September 11, 2012,10:14:26

Hi,
I can't say I'm an expert an inverters, but I have had problems with the Blue
ceramic feedback capacitors, but I would check C421/C424(?) associated with the replaced tx.
Regards,
John.