sharp LC-37SB24U will not power on

[h82loseejr]

the televison does not seem to power on i guess i am wondering how to go about troubleshooting the power supply board as this one is a bit different than others i have troubleshot or dealt with when i plug it in the power light blinks steady off and on for one second if i hold the power putton the power light turns to red and if i hold it again it turns to orange and makes a clicking sound as if it is trying to power up i do not have any voltage coming out of power board to processor/tcon board unless the orange light is on i have tried unplugging the inverter and then the power button will not make a change i am affraid of testing the power going to the inverter board as it seems to be un insulated wires and i do not want to short it out

[nicholas1110]

Re: sharp LC-37SB24U will not power on

Hi,
A steady blink code is a lamp error. On this model it is very common for the lamps to fail. Try this. Unplug the power cord, hold volume minus and input bottons on the tv, while holding these down plug in the power cord. Keep holding, you should see the tv turn on and hopefully flash the backlight or have the backlight stay on for a few seconds. In a dark room see if you can see a horizontal dark streak or sometime pinkish color. This will show you there is a lamp in the screen that is failed. Hope this helps.

[h82loseejr]

Re: sharp LC-37SB24U will not power on

on the power supply i an not getting any voltage at the filter capacitor i am getting 150 out of the bridge rectifier and cannot seem to find what is in between (im a noob) any help would be awsome

the thing that has me stumped now is how does the led on front blink with no power to main filter capacitor
also attaching a picture of compoinent i found with no ohms

i did bump ground when measuring the bridge rectifier and blew the fuse (didnt have a square only buss type so i soldered on board until i get replacment

iv had other projects going on t

[h82loseejr]

Re: sharp LC-37SB24U will not power on

i have tracked down that the relay that turns on the filter capacitor is not closing to get voltage to the filter capacitor....i have had no luck in finding a proper service manual for this either if any one has any direction i can go or knows where to get service manual

thankyou in advance

[budm]

Re: sharp LC-37SB24U will not power on

The relay RL7101 will not turn on until the main board sends the ON signal to the STB pin of the CN7202.
http://www.shopjimmy.com/sharp-rdenc...pply-unit.htm#

Sharp RDENCA272WJQZ (PSD-0552) Power Supply Unit.
Pictures provided by shopjimmy.
So what DCV do you have on the STB pin?
This is going to be tough without proper service manual.

[IK84]

Re: sharp LC-37SB24U will not power on

Wow.. this is small world... I just joined today,I did a search for the model number of this board and this result comes up... crazy part is this is not a 2+ year old post.

I found the service manual for this device if you need it. It doesn't help me since I'm not really a hands on type guy ( though Id like to be)

Not to steal your post, but my device would blink both the OPC and Power button, first the OPC and Power would blink then just the Power.

[IK84]

Re: sharp LC-37SB24U will not power on

The way to find the service manual is you have to search for LC37D44U. I'll post up the service manual, if its not allowed then forgive my ignorance, I didn't see a post saying otherwise.

[budm]

Re: sharp LC-37SB24U will not power on

I already have the service manual (from ELEKTROTANYA.COM) for the LC37D44U and also LC37SB24U since last year, the problem is that it does not have the diagram for the boards, that is why I said it will be tough without the proper service manual.
The model of the TV is sharp LC-37SB24U, not LC37D44U.

[IK84]

Re: sharp LC-37SB24U will not power on

I do not need you to put things in bold for me, I clearly saw what TV the OP was talking about. I was simply trying to help and the research I found when I was looking for help had this to say :

"On the front cover of the LC-37SB24U Service Manual is the statement:

"This Service Manual covers the differences from LC-37D44U. For other technical information, refer to the LC-37D44U (S18D7LC37D44U) Service Manual."

The second line of the second link IS this manual. It appears to be all there, including schematics for the whole set.

To put it another way: The LC-37SB24U is the SAME as a LC-37D44U with the EXCEPTION of what is covered in the LC-37SB24U manual.

"
Source : http://forum.eserviceinfo.com/viewtopic.php?t=82551

[budm]

Re: sharp LC-37SB24U will not power on

There is no power supply board circuit in that service manual you attached, look again, I already has that same manual.
See post 5 for the pictures of the board we are trying to troubleshoot.
Or you can upload the circuit of that power supply if you have it so we can get on with troubleshooting.
See the extracted PDF of SCH and PCB layout from your service manual.

[IK84]

Re: sharp LC-37SB24U will not power on

I apologize then, as I said I'm not a hands on person, and when I reviewed through the service manual I saw the varying board diagrams, just did not take note that the power supply was not one of them.

On a side note : I sadly feel I'll probably have to chuck mine. I can never even get a service menu. I fear its probably not an issue with a board or element on the board, but probably a bad tube, and in that case probably not something I'd be comfortable getting into changing out.

[budm]

Re: sharp LC-37SB24U will not power on

No problem. Most service manuals will not include the pwoer supply section due to most of them use OEM power supplies made by other companies so they are not allow to release the diagrams.
Elektrotanya is a great place for free SCH, Tom66 the member here also has lots of diagrams.
Without diagram I will end up tracing the board using the pictures provided by the people that ask for help, it is very time consuming process.

[michael dranfield]

Re: sharp LC-37SB24U will not power on

I am not sure about this exact model but on the LC32D44 model this fault is caused by bad connections on the lamp ends and sharp supply modified types, on the LC32D44 model the screen is the easiest one to dissasemble I have ever seen , you undo a series of screws , I think its ones marked with arrows and the screen which is mounted in a metal frame just separates from the backlights all in one pice, however after replacing the lamp connectors the error counter has to be reset to zero in the service menu otherwise the set will still not come on.

[michael dranfield]

Re: sharp LC-37SB24U will not power on

Have a read at these guys.

[michael dranfield]

Re: sharp LC-37SB24U will not power on

And this one .

[IK84]

Re: sharp LC-37SB24U will not power on

Very interesting reading. What does it generally mean if you cant see or get to the service menu?

Its been a while now.. but here is my story

I got my tv with the problem from my grandmother. (I might have been responsible for its fail in first place) She was having some problem, I dont remember now what, but I went in and did some tweaking in general settings, and I think.. I cant be sure but I'm positive I tried also to do a firmware update on the tv.

The tv started doing the blinking lights (2 power and 1 OPC) So... Grandmother can't be without her tv so we went out and got her a new one. I felt we should keep her old one so I stored it. A few weeks later I dug it out of garage and took it apart, didn't really do anything but investigate the boards and try firmware in back, but magically the tv came back and lasted with no issues over a year.

Forward to last December and the tv started doing the blinking again, Again I took it apart and tried what I did last time, I got lucky and got another week out of the tv, but then one night while watching a movie POOF just went out and started the blinking. I never saw any bad lighting or bad picture before this.

BTW sorry if I'm hijacking this thread, same tv and same issue it seems so I thought no harm no foul.

[h82loseejr]

Re: sharp LC-37SB24U will not power on

Wow.. this is small world... I just joined today,I did a search for the model number of this board and this result comes up... crazy part is this is not a 2+ year old post.

I found the service manual for this device if you need it. It doesn't help me since I'm not really a hands on type guy ( though Id like to be)

Not to steal your post, but my device would blink both the OPC and Power button, first the OPC and Power would blink then just the Power.

not a problem any help i can get i appreciate it i am trying to get into component level repair and have quite a few to practice on i have bought some equipment and still need some i have fixed a few but this one i am having trouble understanding i only have a basic understanding of the components and what they do i got a ebook on smps repair and it helped some but not as much as i thought it would for 40 bucks

[IK84]

Re: sharp LC-37SB24U will not power on

Yeah, I decided to go further with mine. I opened it up (behind the screen) and saw all the light tubes. They had no signs of darkening anywhere. When I'm doing the service mode combo on the buttons I sometimes wonder if I'm actually getting the TV into service mode.. just cant see it.