LG 55le5400 fuses

[Spector]

Hi,

I decided to dig into this LG 55LE5400 tonight. Symptoms that were described were that the screen wouldn't turn on.

Unfortunately, when I was checking voltages, I slipped up and made an ill advised connection.

Before this mistake, it would give a series of clicks whenever plugged in, and unplugged. It no longer does anything, and on top of that, I killed my DMM.

So, to start digging myself out of the hole I just fell in, I suppose I should start with the fuse that I likely blew.

I'll have to give them a check once I have a new DMM, but assumming that one or both of the fuses on the LGP4247-10 board are open, what size fuse do I need to get for a replacement?

[petehall347]

Re: LG 55le5400 fuses

first post pictures of everything including your dmm with it set up as you were using it .

[Spector]

Re: LG 55le5400 fuses

I wanted to check the voltage regulators, but slipped and bridged two of the legs. I circled the regulator that this happened on in red.

[petehall347]

Re: LG 55le5400 fuses

i dont understand why your meter blew up ..

[Spector]

Re: LG 55le5400 fuses

i dont understand why your meter blew up ..

Fair point.

I'm a complete noob to some of this, and now that I think about it, I think I actually had red on one leg and black on the other. Probably didn't have the meter on any settings that could handle that anyway. It was a complete lapse of judgement.

I've been lucky enough to fix a couple tvs with my little $10 meter, and probably some luck, but tonight was a lesson.

So, TLDR- I contacted one leg of the regulator with one lead, and another with the other. I also likely didn't even have it set for the right voltage.

[petehall347]

Re: LG 55le5400 fuses

did you plug one lead into amps by any chance ?

[Spector]

Re: LG 55le5400 fuses

did you plug one lead into amps by any chance ?

Possibly?

I'll be picking up a new meter tomorrow, and then I'll test the continuity of the fuses to see if that's what I blew.

I just am curious about how I can find out what amperage of fuses they are.

[budm]

Re: LG 55le5400 fuses

That is MOSFET for the PFC Voltage booster circuit, you need to check the RESISTANCE between the Source pin and the Drain pin to see what resistance it shows at this point, you could have also damage the PFC IC or the Bridge rectifier too, need to do lots of resistance checking at this point before attempting to put in new fuse.
Fuse rating is printed right on the board next to the fuse and also on the fuse itself.

[Spector]

Re: LG 55le5400 fuses

That is MOSFET for the PFC Voltage booster circuit, you need to check the RESISTANCE between the Source pin and the Drain pin to see what resistance it shows at this point, you could have also damage the PFC IC or the Bridge rectifier too, need to do lots of resistance checking at this point before attempting to put in new fuse.
Fuse rating is printed right on the board next to the fuse and also on the fuse itself.

Alright. I had some sleep,and I think I'll be a little less dumb now.

Yeah, upon looking at it today, the amperage and voltage rating of the fuse are right there on the board as you said.

As far as checking the resistance on the PFC IC and rectifier, would the expected resistances be printed near them as well? I'll look into it and see what I can find.

I have to order a new fuse anyway. I tested the continuity and it's definitely blown.

Thank you for your time.

[budm]

Re: LG 55le5400 fuses

Check the resistance of that MOSFET you have circle in red, look up the spec sheet so you can which pin is Drain, which pin is Source then report the reading, make sure to indicate if the reading is in OHM, K OHM, M OHM.
Look for the spec sheet of the bridge rectifier so you will understand what are inside and do the research how to test the bridge rectifier.
You need to do the research and collect the data.

[Mr repair]

Re: LG 55le5400 fuses

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