Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

[suriips450]

My Samsung LE46C750 LCD TV has suddenly stopped working, then No PWR, No STBY, No Sound. Removed back cover, had a look at PCBs and found burnt SMT FET-SOT23 (IC1014) which is right on the top side of the power connector on the main board (BN41-01423B/BN94-03388F).

Disconnected main board from power board, turned mains ON then backlight ON.

Please could you let me know that particular FET part number/marking on it?

I would be very grateful to you if you can please share any generic problems with this board causing power failure, blowing that FET and any schematics.

Ordered a DMM, need to order solder iron and then components when I progress!!

Many Thanks

[tw2005]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

A really good photo of it would be handy. Are you sure it's a FET? Normally transistor would have a Q designator, IC sounds like it could be something else?

[suriips450]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

Hi tw2005,

Thanks for your reply. I agree with you about designators and I am sure it's a FET, please see attached images. Do you reckon two ceramic caps next to that FET may be gone as well?

Thanks for your help.

[tom66]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

Looks like a voltage regulator to me.

[suriips450]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

Thanks for your comments tom66.

TV is just over 2 years old. Please can you recommend me a part number that I can fit as a replacement? Any idea what could have caused it?

[tom66]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

I have used up all my free downloads. Can you see if either of these have a parts list?

http://elektrotanya.com/samsung_le46.../download.html

[suriips450]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

Thanks for that tom66. I do that rightnow. Would you advise me changing caps as well on the PSU as they are more than two years old. I haven't got ESR tester to test those caps, rather than buying a ESR tester I am thinking about just replacing them along with that voltage regulator.

[tom66]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

Hmm, I have not heard of any bad caps on C-series Samsung so I think you will be OK.

[suriips450]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

That's great. Thanks for that.

[suriips450]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

Hi tom66,

I did manage to downloaded pdf files from the link that you provided, thanks for that.

Sorry for the trouble, I couldn't find IC1014 on the BOM, please can you help me by looking at this attachment?

Thanks

[tom66]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

I can't find it either, that parts list does not look complete to me.

[suriips450]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

Thanks for that, I will check on that website again. Thank you

[suriips450]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

Is there any other source for getting BOM apart from the one you provided earlier? Thanks

[tom66]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

Only from Samsung directly who are unlikely to tell you or someone on ebay who may be really nice and read it off for you...

[suriips450]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

ohh nooo!! Thanks for your help. I will post how I got on. One last question if that's okay, did you come across similar issue before (burnt IC)? What are other possibilities that I should look for please?

[tom66]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

Sometimes there are other faults on a board leading to that fault. Other times the fault is independent. Not seen one like this yet.

Whole boards kit... says it contains main board but no picture? Check with seller 1st.
http://www.ebay.co.uk/itm/SAMSUNG-LE...item4accee2f49

Board is available for nearly £70
http://www.ebay.co.uk/sch/i.html?_od...1423B&_sacat=0

or maybe less?
http://daimelectronics.co.uk/product...roducts_id=314
http://www.lcd-plasma-parts.co.uk/in...oduct_id=13457

[suriips450]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

Thanks for that. I will get in touch with first link you sent, as it's more specific to 46" (BN94-03388F) where as others for 40" (BN94-03388E) & out of stock. OR do you reckon both are same?

Many Thanks for your help

[tom66]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

46" and 40" boards should be compatible as both use Samsung panels and you can usually change setting in service menu anyway. Only difference is the setup menu will report model # incorrectly... hardly a problem.

[suriips450]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

Cool, thanks for confirming. I was thinking about there may be firmware difference as to drive video signals to bigger screen and things like that!

[tom66]

Re: Samsung LE46C750 No PWR, No STBY (Burnt FET on AV Board) Please Help!

The panel electronics themselves handle all of that. No worries.