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Anthony_Infotech
Anthony_Infotech, Technician
Category: TV
Satisfied Customers: 10168
Experience:  20+ years experience TV expert in the main
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Hi support, I have a Sharp TV model LC-42SV49U which i am

Customer Question

Hi support,
I have a Sharp TV model LC-42SV49U which i am trying to fix. i need some help as i dont have the schematics for any of the internal boards. The issue is i plug in the power cord to the tv, i get nothing, no lights, no standby lights no relay clicks... nothing. so i think its the power supply. i have fluke mutli-meter to check various dc/ac voltages. its not fuses becuase i can see 120 volts ac coming into the bridge rectifier and 160 volts dc coming out of the rectifier. i also attempted to check for possible output voltages from the capacitors of the final filter circuit going to the wire harnesses, which lead to the other boards, i dont see any voltage, i dont have a schematic or specs so maybe you can help.
Submitted: 1 year ago.
Category: TV
Expert:  Anthony_Infotech replied 1 year ago.
Hello my name is Anthony
Welcome
Thanks for the Question

It would be better if you just replaced that powerboard complete in most instances with faults on the boards replacing the board is the best option because of the logistics in trying to repair to component level, now if you post back to me any info you find on sticky labels on the power board I will look for a board for you

Let me know please

Anthony
Customer: replied 1 year ago.

Hi Anthony, this is the second board i ordered and both have the same symptoms, and both ebay sellers have money back guaranty reburbished and will accept returns... how can both boards be DAO... can i get a brand new from sharp?

Expert:  Anthony_Infotech replied 1 year ago.
Hi

Thanks for the extra info.

Ok you need to measure on the output plugs of the powerboard that go off to the mainboard (the one with the AV connectors on)for voltages like 5volts 3.3volts 12volts all dc red lead to the metal pin on the plugs black lead to metal chassis

Let me know if you get any voltages

Let me know any info on labels on the ORIGINAL powerboard that was in the set

Anthony
Customer: replied 1 year ago.

ok, black is ground/chassis


red no voltage


yellow no voltage


green no voltage


brown no voltAGE


orange i see 5 volts.


 


i assume red should have at least 12 to 24 volts, since the output caps are rated for 50 volts.


 


my thought is


1) the mainboard(av connectors) sends the signal to turn on the output stage of power supply, which is not happening OR


2) i have another DOA power supply board.


 


Here is the s/n numbers of the original board:


silkscreened on board: 491A014G1400R


 


NUMBERS ON STICKER:


H 795951400500R H9B50AAL11GR 1142 (E1)

Expert:  Anthony_Infotech replied 1 year ago.
Hi Rich

This is the powerboard you should have for replacement

http://www.tristatemodule.com/p-22922-9jy795951400500r-sharp-tv-module-power-supply-lc42sv49u-lc42d69u.aspx

The 795951400500R is the partnumber

If that 5volts doesnt go low when you press the on off switch on the set itself then you could have a bad mainboard

The mainboard is here

http://www.tristatemodule.com/p-22923-9jy796051300500r-sharp-tv-module-main-board-lc42sv49u.aspx

I trust the above site for parts ebay is OK but sometimes things are bad

Let me know if you need more info

Anthony

Anthony_Infotech, Technician
Category: TV
Satisfied Customers: 10168
Experience: 20+ years experience TV expert in the main
Anthony_Infotech and 5 other TV Specialists are ready to help you

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