Little Help with Sharp LC-80LE642U

[Robottom]

Re: Little Help with Sharp LC-80LE642U

BUMP

Does any one know what / where these chips are that Martino mentioned?
If there's an easy fix of any kind, I'll give that a try but pretty much tomorrow is the end game for this thing. I promised we'd have our TV back by then, so it's off to Costco for a new one and parts for sale after that.

Thanks,
Tom

[dick_barton]

Re: Little Help with Sharp LC-80LE642U

Have you tried to bring on the panel leds without the mainboard connected to ensure they stay on, by jumping PS_ON to standby voltage using a 1K resistor

[Robottom]

Re: Little Help with Sharp LC-80LE642U

Have you tried to bring on the panel leds without the mainboard connected to ensure they stay on, by jumping PS_ON to standby voltage using a 1K resistor

No, I asked if there was a way to do that in my original post, "Fool the power board" but didn't get any feedback.

Will go try that now and let you know what happens.

Thanks

[Robottom]

Re: Little Help with Sharp LC-80LE642U

Nothing, the power board doesn't even try to output to the LEDs.

There must be some other signal from the main board that tells the power board everything is OK. Do you know what other signals from the main board I would have to fake?

And as for being no expert, I'm sure that I have you way beat, thanks anyway!! :-)

[dick_barton]

Re: Little Help with Sharp LC-80LE642U

Taking a look at some earlier readings given on the power supply it looks like the standby voltage is BU5V (Pin15). So with this jumped (using resistor) to PS_ON (Pin14) do the leds come on. Normally there is another connection such as BL_On/OFF but I cannot see anything marked like that.

When you do jumper BU5V to PS_ON what voltage do you have at the STB pin (Pin 24)?

[Robottom]

Re: Little Help with Sharp LC-80LE642U

Taking a look at some earlier readings given on the power supply it looks like the standby voltage is BU5V (Pin15). So with this jumped (using resistor) to PS_ON (Pin14) do the leds come on. Normally there is another connection such as BL_On/OFF but I cannot see anything marked like that.

When you do jumper BU5V to PS_ON what voltage do you have at the STB pin (Pin 24)?

With BUSV pin 15 jumped to PS_ON pin 14 through 1K Ohm resister, I'm still not getting the LEDs to turn on, and measuring only 14 - 15mV at STB pin 24.

[Robottom]

Re: Little Help with Sharp LC-80LE642U

Just trying a couple of things to get the LEDs on using the power board, I went back to this idea that I talked about earlier: See attached pic.

This guy actually powers up STB as well as PS_ON from BU5V but no resistor.
Anyway same as what you said he's also powering something else PWM1.
But I don't see anything on this power board with those markings or the markings BL_ON you mentioned.

I tried powering STB through the resistor from BU5V too and still same, no LEDs lighting up.

There is a PNL_POW but I haven't tried that yet.
His instructions require a step order of powering up that I don't have switches for not to mention no idea what might blow up if I do.

[budm]

Re: Little Help with Sharp LC-80LE642U

It looks to me that he is referring the 'STB' to be the same as 'BL-ON' which may be the case for the Sharp TV.
I would never try to force on anything without using the resistors because if you made the wrong connections you can cause more damage, the resistor is used to limit the current.
The PNL-POW is the control signal from the main board to turn on the switched 12V (PNL-12V) for running the T-CON board, you do not need that signal to test the backlights circuit.

[Robottom]

Re: Little Help with Sharp LC-80LE642U

Question... Assuming that I can get the power board to light the LEDs without being connected to the main board, where do I go from there?

I've already replaced all three boards and have exactly the same symptoms as from the beginning.

Assuming that the boards are OK, something else must be wrong.
Example: overcurrent from the LEDs or possibly LCD panel error of some kind via TCon. (would mean that the flashing icon 1 short 1 long is misleading).

Are there any chips or components in the LCD panel section that I am not seeing?

[Robottom]

Re: Little Help with Sharp LC-80LE642U

With
BUSV (pin 15) jumped to PS_ON (pin 14) through 1K Ohm resister,
STB (pin 24) jumped to PS_ON (pin 14) through 1K Ohm resister and
PNL_POW (pin 16) jumped to PS_ON (pin 14) through 1K Ohm resister
I get a short flash of the LEDs at power up and again at power down.
Nothing seems to keep the LEDs on longer than a short flash.

Are there any other tests than powering the strips with the LED tester that I can run on the LED strips to be 100% sure that they're not one and only problem?

[budm]

Re: Little Help with Sharp LC-80LE642U

STB (pin 24) jumped to PS_ON (pin 14) through 1K Ohm resister and
PNL_POW (pin 16) jumped to PS_ON (pin 14) through 1K Ohm resister
One end of those resistors should go to BU5V pin, not PS-ON pin.
May be you should buy the LED tester.

[martino]

Re: Little Help with Sharp LC-80LE642U

May be you should buy the LED tester.

Agreed,it's not the panel as you tested that.

I have this one, works awesome.
http://www.ebay.ca/itm/LED-LCD-TV-Ba...QAAOSwnNBXYlGC

A 80" tv is worth the effort you put into it and then some.
Maybe pick a el cheapo tv up from craigslist for the time being to keep the better halve at bay?

[Robottom]

Re: Little Help with Sharp LC-80LE642U

Agreed,it's not the panel as you tested that.

I have this one, works awesome.
http://www.ebay.ca/itm/LED-LCD-TV-Ba...QAAOSwnNBXYlGC

A 80" tv is worth the effort you put into it and then some.
Maybe pick a el cheapo tv up from craigslist for the time being to keep the better halve at bay?

Thanks for the encouragement, I'm pushing back.
I finally decided to hire someone to come out and help troubleshoot.
Drops another $50 into the bucket but if I can get it working beats the heck out of $2K or more.

I bought the tester several posts back, the exact same one in your link.
That's what I used to test and post the results that the LED strips were reading 174 - 175VDC.

ALSO .... I'm still curious about your (Martino) previous comment about chips burning up, pulling ribbon cables to test, getting half a screen working and being an easy fix.
Could you please go back over that again and let me know where / if there is some component / chips in the LCD panel that might be the problem.

[budwich]

Re: Little Help with Sharp LC-80LE642U

read up on the numerous sharp 70 threads that provide LOTS of "cable pulling" examples / discussion. Look for "corner cable" posts/discussion... hint, there are cables in the lower corner and each side that connect the lower edge boards to the side boards. 2 5 flash code is common BUT the system isn't always good as to what codes are output. It is rather strange that you are unable to force the set to come up with back lights on especially with the amount of card changes that you have done... assuming those are good.

[Robottom]

Re: Little Help with Sharp LC-80LE642U

read up on the numerous sharp 70 threads that provide LOTS of "cable pulling" examples / discussion. Look for "corner cable" posts/discussion... hint, there are cables in the lower corner and each side that connect the lower edge boards to the side boards. 2 5 flash code is common BUT the system isn't always good as to what codes are output. It is rather strange that you are unable to force the set to come up with back lights on especially with the amount of card changes that you have done... assuming those are good.

I have been scratching my head and wondering what edge boards and corner cables were.
I found this (https://www.badcaps.net/forum/showth...+cables&page=6) scroll down to #105 - 106, and some other threads which I think explain but I don't have any of those boards or cables.

Here's what my LED back panel looks like and here's what my LCD panel looks like. Although this pic is just one corner, believe me, there are no connections or boards except for the ones coming from the Tcon to the LCD.

I paid a tv tech to come out to my house and troubleshoot. He said the new main board that I received had exactly the same problem as the one that I need to replace. I've sent that one back to Secure Core (who by the way gets kudos from me, free return and full refund, they didn't have another in stock but ...) I have another one on order, should be here Tuesday. I'll post then hoping that turns out to be the problem, regardless, I had to promise it's the end of the line win, lose or draw. If it's not back on the wall working Tuesday night I'm off to Costco to buy a new something or other.

[dskall]

Re: Little Help with Sharp LC-80LE642U

Is that your wife's side of the bed you got the panel on?

[budwich]

Re: Little Help with Sharp LC-80LE642U

I have been scratching my head and wondering what edge boards and corner cables were.
I found this (https://www.badcaps.net/forum/showth...+cables&page=6) scroll down to #105 - 106, and some other threads which I think explain but I don't have any of those boards or cables.

Here's what my LED back panel looks like and here's what my LCD panel looks like. Although this pic is just one corner, believe me, there are no connections or boards except for the ones coming from the Tcon to the LCD.

I paid a tv tech to come out to my house and troubleshoot. He said the new main board that I received had exactly the same problem as the one that I need to replace. I've sent that one back to Secure Core (who by the way gets kudos from me, free return and full refund, they didn't have another in stock but ...) I have another one on order, should be here Tuesday. I'll post then hoping that turns out to be the problem, regardless, I had to promise it's the end of the line win, lose or draw. If it's not back on the wall working Tuesday night I'm off to Costco to buy a new something or other.

:-) but I think you are looking at the wrong side / face.
there are edge boards on the sets in some form. Just as you see the bottom edge boards connected to the panel with "tab driver flex cables", there are similar cables connecting the sides either to a board or to a long flex cable that act like a board.
Anyways, it must be tough sleeping with the TV... :-)

[Robottom]

Re: Little Help with Sharp LC-80LE642U

Is that your wife's side of the bed you got the panel on?

No but she's threatening to make that one my permanent bedroom.

[Robottom]

Re: Little Help with Sharp LC-80LE642U

:-) but I think you are looking at the wrong side / face.
there are edge boards on the sets in some form. Just as you see the bottom edge boards connected to the panel with "tab driver flex cables", there are similar cables connecting the sides either to a board or to a long flex cable that act like a board.
Anyways, it must be tough sleeping with the TV... :-)

I only see a black rim around the LCD section.
I haven't taken that apart but have inspected it pretty carefully and there are no visible boards or cables.
Is it possible that the edge panels and cables are integrated into the LCD Panel Module Unit on this model?
Have a look at the Cabinet Layout attached.

These pages are extracted from the LC-80LE642U Service Manual
I don't see anything that I don't recognize in the PCB or Parts lists either.

At least the TV isn't complaining :-)
The wife on the other hand ......

[budwich]

Re: Little Help with Sharp LC-80LE642U

The reason that there is no listing for the boards is that they aren't replaceable as there is bonded cabling between the board and the panel which is a "one time assembly / manufacturer". Anyways, I would look closer at the edge especially going from the tcon to the panel at the bottom. Your issue may be related to how the edge boards are interconnected which could be good or bad depending.