Sharp Aquos LC52SE94U hit by surge

[Fwrothy]

Re: Sharp Aquos LC52SE94U hit by surge

Bridge is open...

[Fwrothy]

Re: Sharp Aquos LC52SE94U hit by surge

Bridge is open now with J7027 back in place

[budm]

Re: Sharp Aquos LC52SE94U hit by surge

OK, then take the resistance reading between Source and Drain pin of MOSFET Q7808, it should show very low resistance.

[Fwrothy]

Re: Sharp Aquos LC52SE94U hit by surge

.3 ohm

[budm]

Re: Sharp Aquos LC52SE94U hit by surge

OK, now remove it and test again. If it is still short, you will have to replace it and also the PFC IC (IC7800) that drives this MOSFET at the same time.
It is late here so I am going bed, at least we are getting some where.

[Fwrothy]

Re: Sharp Aquos LC52SE94U hit by surge

It's later here-thank u very much! Great troubleshoot practices and knowledge to go with. Great progress...
I'm optimistic (-:

[Fwrothy]

Re: Sharp Aquos LC52SE94U hit by surge

Most sure blown primary transistors, maybe controller too.
In diode mode, check all the transistors that are near the bridge rectifier. I any causes "beeeep!" or near 0 ohms, then its dead.
Remember the nice bulb trick, if you replace anything always test with the bulb, because if something is still bad it will blow again breaking the new parts, or maybe more!

Sound advice thank you!

[budm]

Re: Sharp Aquos LC52SE94U hit by surge

Here is the simplified diagram and the how that shorted out MOSFET is connected.

[Fwrothy]

Re: Sharp Aquos LC52SE94U hit by surge

Very nice sketch Budm, I will definitely file that.

So I got the 6R199P MOSFET out and the source and drain are indeed shorted.

Made some notes as well and look around at possible sources. Haven't looked into the ic yet will start to recearch it and hopefully do some one stop shopping(still need fuses too).

[tom66]

Re: Sharp Aquos LC52SE94U hit by surge

Is that all that's printed on the device?

[budm]

Re: Sharp Aquos LC52SE94U hit by surge

Make sure to put that Ferrite bead back on the leg of the new MOSFET. That part is not in the service manual?

[Fwrothy]

Re: Sharp Aquos LC52SE94U hit by surge

Is that all that's printed on the device?

No it's it's also got GAJ745 at 90 degrees on the right side of case. Sorry I'm struggling a bit since all my equip is sub par. Couldn't find my my magnifier so resorted to a long camera lens

[Fwrothy]

Re: Sharp Aquos LC52SE94U hit by surge

Make sure to put that Ferrite bead back on the leg of the new MOSFET. That part is not in the service manual?

Meant to ask you about that since I noticed them, what is the purpose of these, some sort of mag flux or inductance insulator or just straight up insulation?
Going to down load that manual, I assume you mean the one Tom66 suggested; will put it on my laptop, been doing this with the iPad and can't figure how to DL properly.

[tom66]

Re: Sharp Aquos LC52SE94U hit by surge

It reduces the high frequency noise that can radiate off that pin. Such noise can cause problems with getting EMC compliance.

[selldoor]

Re: Sharp Aquos LC52SE94U hit by surge

https://cdn.badcaps-static.com/pdfs/...c455e8e65f.pdf

[tom66]

Re: Sharp Aquos LC52SE94U hit by surge

Selldoor always has a knack of finding these. Looks like the right part.

[selldoor]

Re: Sharp Aquos LC52SE94U hit by surge

Digikey
http://www.digikey.co.uk/product-det...9CP-ND/2080865

Also on ebay from China

[Fwrothy]

Re: Sharp Aquos LC52SE94U hit by surge

https://cdn.badcaps-static.com/pdfs/...c455e8e65f.pdf

Yup that where I found my inf too

[Fwrothy]

Re: Sharp Aquos LC52SE94U hit by surge

I noticed a difference in case types some have metal heat sinking tabs, this one is all ceramic. Designation TO262? What is the script on the right side batch?

[selldoor]

Re: Sharp Aquos LC52SE94U hit by surge

I noticed a difference in case types some have metal heat sinking tabs, this one is all ceramic. Designation TO262? What is the script on the right side batch?

Not sure what you are saying? They also make this one in a TO262
https://cdn.badcaps-static.com/pdfs/...85b4988db2.pdf

But again it is all ceramic.

SORRY - that is an N channel

LATE EDIT

Damn they are both N channel