Hi All.
I would still class myself as a novice when it comes to component level fault finding and repair.
I am trying to repair a Samsung PS-42V4S 42" Plasma TV.
When mains power is applied the standby led comes on, when you try to power on the tv (come out of standby) the standby led flashes, but the display does not light up.
My first port of call was to check all the glass fuses on the PCB, as well as the TH fuses, all are fine.
My second port of call was to start checking all the output voltages.
None of the output voltages from the SMPS had any voltage, so I started working my way back.
I have 340vdc at the switching mosfet for the smps, but it appears that there is no signal to the gate of the mosfet.
I have traced back as far as IC1 the power factor correction ic, and I am not getting the kind of voltages that I would be expecting on some of the pins, and no voltage at all on pins 2&4.
I am thinking that this IC has failed, or that something else is making this IC act funny.
The IC in question is a
ML4824 - Power Factor Correction and PWM Controller Combo. <Click for Datasheet.
Thanks for your time.
Best Regards.