Samsung PS50B430 Y-main Fault?

[netdent]

I have this samsung plasma, came to me with clicking syndrome! Narrowed it down to the y main board, on closer inspection on the y board small 1 amp fuse open, never had solder in fuse to hand so soldered 2 wires and crock clipped 1amp fuse inline, powered on no clicking but an smd resistor smoked slightly followed by clicking psu again, fuse remained intact! the voltage across the fuse is 15 volts.

I removed the y board and found a shorted fet circled red in picture IRFP4332 there are 2 of these the other read ok, I replaced the shorted fet and fitted back in, the set powers on and makes the right noises but screen is blank. I'm thinking still a problem on this board? all psu voltages read correct

The previous owner changed the LDVS board, and also tried to fit an incorrect y board? but think there was no damaged caused by this.

not sure where to go now, maybe the smoking resistor is toast? difficult to get at with the heatsink, any advice welcome

thanks Ronnie

[PlainBill]

Re: Samsung PS50B430 Y-main Fault?

I have this samsung plasma, came to me with clicking syndrome! Narrowed it down to the y main board, on closer inspection on the y board small 1 amp fuse open, never had solder in fuse to hand so soldered 2 wires and crock clipped 1amp fuse inline, powered on no clicking but an smd resistor smoked slightly followed by clicking psu again, fuse remained intact! the voltage across the fuse is 15 volts.

I removed the y board and found a shorted fet circled red in picture IRFP4332 there are 2 of these the other read ok, I replaced the shorted fet and fitted back in, the set powers on and makes the right noises but screen is blank. I'm thinking still a problem on this board? all psu voltages read correct

The previous owner changed the LDVS board, and also tried to fit an incorrect y board? but think there was no damaged caused by this.

not sure where to go now, maybe the smoking resistor is toast? difficult to get at with the heatsink, any advice welcome

thanks Ronnie

Definitely a problem with the Y main. Yes, it could be the resistor, or it could be some other problem. Troubleshooting these are very difficult due to a lack of schematics and the fact that they deal with high frequency (200 Mhz), high voltage (>200 volt) signals.

PlainBill

[netdent]

Re: Samsung PS50B430 Y-main Fault?

Definitely a problem with the Y main. Yes, it could be the resistor, or it could be some other problem. Troubleshooting these are very difficult due to a lack of schematics and the fact that they deal with high frequency (200 Mhz), high voltage (>200 volt) signals.

PlainBill

Thanks PlainBill, might need to try and source a used part? not sure if I will be able to read the value of the resistor if it is open, guess it will also need to be read out of the board

Ronnie