sharp LC-40E67UN death set no stand-by

[hmendez86]

No power at all. No 5v on the power supply,,,fuse are good and rectifier good.....transistor are good too....

[budm]

Re: sharp LC-40E67UN death set no stand-by

Pictures, pictures, pictures.

[hmendez86]

Re: sharp LC-40E67UN death set no stand-by

[budm]

Re: sharp LC-40E67UN death set no stand-by

Sharp RDENCA354WJQZ (DPS-208BPA) Power Supply Unit.
http://www.shopjimmy.com/sharp-rdenc...wer-supply.htm

OK, SJ does not have the pictures of the bottom side of the board, please take good straight shot pictures of the bottom side of the board so I can give you the test point to test.
History of the TV?
I can see some fusible resistors (Low Ohm white ceramic body resistor) on the board.

[R_J]

Re: sharp LC-40E67UN death set no stand-by

Its hard to tell from the picture but I think the area I outlined may be the standby circuit, What is the number on the ic I outlined in yellow? it may be one of those TNYxxx ic's, they like to go bad.

[hmendez86]

Re: sharp LC-40E67UN death set no stand-by

[dick_barton]

Re: sharp LC-40E67UN death set no stand-by

This looks very similar
http://jestineyong.com/samsung-lcd-tv-repair/

[budm]

Re: sharp LC-40E67UN death set no stand-by

Hate to say this, but that jestineyoung info is wrong about that 2.2 Ohm resistor, it is not for the Source pin of the STBY SMPS IC7905, if you look at the IC spec and the application circuit, you do want to put the resistor on that Source pin.
If he traced out the board, he would have seen that R7918 (2.2 Ohms) is connected to D7918 which is the rectifier for the AUX winding of the SMPS transformer to produce the DC filtered by cap C7915. So check that to see if it is open or not.
There is a fusible resistor R7914 that feed the main B+ for running the STBY IC7905.
BTW, I wish the bottom side picture is a straight shot and no glare but was enough to see how the STBY SMPS IC is connected.
It looks like someone did some works on the board, some of the solder joints do not look good.

[CapLeaker]

Re: sharp LC-40E67UN death set no stand-by

Did you check if the output on the secondary of the STBY voltage pin is shorted?

If there is no shorts there, than the problem has to be on the primary side. Usually either the resistor that budm is talking about is bad or the rectifier diode with it's filter cap. The STBY IC can fail too...
Yep, looks like someone was already working on that board.

[hmendez86]

Re: sharp LC-40E67UN death set no stand-by

I had luck i just replace the 5v stanby IC7905 and it work fine.....thanks for help well keep for records..

[CapLeaker]

Re: sharp LC-40E67UN death set no stand-by

Very good! Sometimes the PWM (IC7905) fails, not usually, but it does. Thanks for the update!

[neilc6]

Re: sharp LC-40E67UN death set no stand-by

I have the same TV and replaced a blown TNY264PN but still have no standby voltage. R7918 measures 2.4 ohms and I can't find R7914. Will keep looking. All diodes and the single transitor test ok in that area of the board. Main filter cap measures 165VDC which is low.

[dskall]

Re: sharp LC-40E67UN death set no stand-by

165v is not low for standby

[neilc6]

Re: sharp LC-40E67UN death set no stand-by

Ok found R7914. It is under the bottom shield and measures open. 2.2 ohm 1/2W? Marked W1/2J 95K.

Found this thread for finding a replacement https://www.badcaps.net/forum/showthread.php?t=36749

This thread applies as well https://www.badcaps.net/forum/showthread.php?t=24435

Shopjimmy repair kit (RDENCA336WJQZ) replaces IC7905 , D7908, R7914, and 7918