Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

[pk7tanner]

I had made a previous post about this set https://www.badcaps.net/forum/showthread.php?t=43199
Well, the problem was getting worse, so I tried entering into the factory reset mode while it was happening. When I couldn't get it to fix the problem, I just turned the set off. Now it won't even power on. When I try to reenter reset mode, it turns on for 2 seconds, then shuts off.
Also, while browsing the Sharp manuals, I haven't been able to find one that is similar to this model.

[pk7tanner]

Re: Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

Found the manual, so please disregard that.

[pk7tanner]

Re: Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

Bump
Hopefully someone has a little insight for me.

[nuala]

Re: Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

Any blinking code?

[newtothis]

Re: Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

Multimeter to hand?

[pk7tanner]

Re: Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

No blinking code other than the front power LED blinking at a constant rate.
Yes, I have a multimeter.

[newtothis]

Re: Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

Connector from PSU to Main. Check pins at PSU side with DMM set to DCV. If there are voltages written by the connector write the results out like this for EG:

12v - 0v
PS_ON - 3v
STBY - 5v

etc
etc

You labels may vary

[pk7tanner]

Re: Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

Sorry for taking so long. The only one with voltage is the BU5V which has 5v.
I have another question. I was checking the MOSFETs on the power board. Since I'm a novice and can't decipher data sheets, I check them against their matching counterpart. One of the st 13nm60n gives a reading of .955, while the others read OL. I'll attach a photo of the suspect fet.

[pk7tanner]

Re: Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

Here's the data sheet. http://www.st.com/web/en/resource/te...CD00261517.pdf
If someone can give me the v readings I should get, that would work as well.

[newtothis]

Re: Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

Before we jump into MOSFET testing etc can you provide the voltage readings in the format of post #7 please. This way we can see what the pin labels are

[pk7tanner]

Re: Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

OK

UR13V = 0
UR13V = 0
UR13V = 0
UR13V = 0

ACDET = 0
PS_ON = 0
BU5V = 5v
PNL_PWR = 0

UR13V = 0
UR13V = 0

PNL12V = 0
PNL12V = 0

No voltage on any of them other than BU5V which had 5 volts

[newtothis]

Re: Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

OK does the PS_ON pin get any voltage with all boards connected and you attempt to power the set up?

[pk7tanner]

Re: Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

If the set is plugged in, you get no response from the buttons. There's just the flashing green light at the front.
I'll have to wait until someone can help me push the power button while I hold the dmm lead

[pk7tanner]

Re: Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

No the set turns on and immediately goes into safe mode or whatever mode it's in. Hitting the buttons shows nothing.

[budm]

Re: Sharp LC-52LE700UN was working with an occasional white screen issue, stopped

Service manuals:
http://elektrotanya.com/?q=showresul...at2=schematics

Are you sure that the blinking LED does not have any flashing pattern?
I expect AC DET to be around 3V but not 100% sure.