Sharp LC-90LE745U 3 slow and 1 fast Blink

[RDC55]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

It does solve one issue in that the STB pin on Sharp TV is associated with the backlight circuit and not a standby pin as common sense would dictate. What the acronym STB stands for is anyone's guess, but the Asian nomenclature for LED's seems to often be referred to as "beads."

Still iffy on the error signal, it would be nice to know if it could be tricked out in some way, but still not quite enough information to make a suggestion.

[c00lman]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

Not the exact one but the Power Supply schematic is likely a close match using the same backlight controller ASIC - courtesy of member lotas.

https://www.badcaps.net/forum/showthread.php?t=97281

Thank you.. we'll see if I can trace something hahaha

[RDC55]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

Not the exact one but the Power Supply schematic is likely a close match using the same backlight controller ASIC - courtesy of member lotas.

https://www.badcaps.net/forum/showthread.php?t=97281

[c00lman]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

Yeah. Was hoping there’s a back door trick into the service menu . Order it from the US not sure if we can put the URL here lol

Unfortunately. It’s hard to get parts within canada .

It’s nice to get this baby back in service but it might cost a lot more than just to give up

Just the main board alone is around $100 + shipping + import fees etc .

Wish we have stores like that here. Lol

[RDC55]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

Darn, I was hoping a firmware update along the way had made the entry into the service menu different than the service manual and that was going to work.

Logic seems to say then that the Main is not doing what it is supposed to do - ignore the fault and power up with a "K." Maybe I don't understand the process.

Where are these boards coming from, and do you trust the vendors? Didn't the first replacement have an overheating part?

This listing on Ebay is expensive, but worth every bit if it gets a 90 inch TV back in service. And, really good positive feedback at 100%.

https://www.ebay.com/itm/17412849480...IAAOSwJ2td-Ow2

[c00lman]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

Hello, yes plug the tv in first. This procedure to enter service mode can be done even with the blink code

1. Plug tv in.
2. Press and hold volume - and input buttons, while holding them, press the power button.
3. Tv will turn on, with the letter k on the screen.
4. Press and hold volume - and channel down.
5. Service menu will appear, you should see lamp error in the list, set to 0 if it is anything higher.

hi, plugging the TV in goes immediately to that 1-1 blink then press and hold volume - and input buttons while pressing the power button does not do anything.. it continue to do the 1-1 blink LOL

[nicholas1110]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

Hello, yes plug the tv in first. This procedure to enter service mode can be done even with the blink code

1. Plug tv in.
2. Press and hold volume - and input buttons, while holding them, press the power button.
3. Tv will turn on, with the letter k on the screen.
4. Press and hold volume - and channel down.
5. Service menu will appear, you should see lamp error in the list, set to 0 if it is anything higher.

[c00lman]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

To get into service mode on some sharp models it's not like the older ones. First plug in the power, then press volume - and input together and while holding those press the power button. Continue to hold until the tv powers on without the blink code ( should be pretty fast) when the k shows up release the power and input and press and hold channel -

Hope this helps

do we plug in the power first then press volume - and input together? when I plug in the power, the TV goes to the 1-1 blink

i will try it again later

thank you

[nicholas1110]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

To get into service mode on some sharp models it’s not like the older ones. First plug in the power, then press volume - and input together and while holding those press the power button. Continue to hold until the tv powers on without the blink code ( should be pretty fast) when the k shows up release the power and input and press and hold channel -

Hope this helps

[c00lman]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

Thanks.. that's what I'm thinking.. will put it in storage for now and hopefully I can find a working power supply to test it. since the back light seems to be working (not 100% confirmed as can't really open up and check each light hahaha).

or I might just sell it for parts.

Thank you again.

[RDC55]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

I was thinking of the entire bottom of the Power Supply, but it's pretty much a dead end trying to find any meaningful information on that LED controller so the additional picture is not going to help much for now.

Nice picture though with some really good detail.

[c00lman]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

Yup. Holding the input and volume down key longer does the same thing. It looks like going to boot and display the k but it shutdown after backlight flashed.

Also took a pic of the ic underneath the power supply. Are you referring to this one?

[c00lman]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

"That is the procedure I'm following, pressing the Input and Volume down while plugging the AC power, the main board LED will blink, then after few seconds, I will hear the power Hum indicating it's activating the backlight, then the back light will flicker then power supply shutdown and the indication is doing the 1-1."

And you have continued to hold the volume v and input for a good 20 to 30 seconds after plugging in the set, just in case the main has to boot to a point to recognize the command.

Yup. I will try it again tonight . Just outside

[RDC55]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

"That is the procedure I'm following, pressing the Input and Volume down while plugging the AC power, the main board LED will blink, then after few seconds, I will hear the power Hum indicating it's activating the backlight, then the back light will flicker then power supply shutdown and the indication is doing the 1-1."

And you have continued to hold the volume v and input for a good 20 to 30 seconds after plugging in the set, just in case the main has to boot to a point to recognize the command.

[c00lman]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

Thank you for the reply, yeah.. I was hoping for a huge voltage or current difference on the strip to indicate it's a strip issue but they are almost identical

I will take a pic of the back of the power supply board.

That is the procedure I'm following, pressing the Input and Volume down while plugging the AC power, the main board LED will blink, then after few seconds, I will hear the power Hum indicating it's activating the backlight, then the back light will flicker then power supply shutdown and the indication is doing the 1-1.

Also, using the laser temperature measurements, the power supply board seems to be warming up. not sure if it's because of the heatsink of the LED strip Regulators but it seems that the board is hotter than the heatsink lol

My first thought is that would have been one hundred and something mA's, but not that important right now. I would add that the similarity between all of them suggest there is not a problem with the strips.

I pieced together a 60 inch just to see what state "error" is when safe. From what I have read on this site and the test I did error is low when safe, you do have a high but the logic doesn't necessarily have to follow the smaller sets.

On the 60 inch, which is quite a bit different the STB pin must be high for the backlights to come on at full current. The PWM signals will put the backlights in a soft start condition with STB low, but when STB goes high PWM signal goes from high to active adjusting the brightness. I guess the point here is that to force the backlights STB would need to be held high, but the dilemma then comes with what to do with SDA, SCL, and VCLK - just opening this thought for discussion.

Perhaps the LED controller has a datasheet, so maybe post a clear pic of the backside of the Power Supply and see if you can get the numbers off that IC, which is IC7201 an 80 pin IC. It might be a dead end if no datasheet exists, which is fairly common.

I suspect you have done it right but just to be sure when trying to enter the service menu you are starting with the TV unplugged and following the steps below:

Entering the adjustment process mode
1)Press and continue to hold the VOL v & INPUT buttons while plugging in AC power.
2)Continue to hold the VOL v & INPUT buttons until <K> appears on the top left side of the Display


Have you tried the reset with the latest board?

[RDC55]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

My first thought is that would have been one hundred and something mA's, but not that important right now. I would add that the similarity between all of them suggest there is not a problem with the strips.

I pieced together a 60 inch just to see what state "error" is when safe. From what I have read on this site and the test I did error is low when safe, you do have a high but the logic doesn't necessarily have to follow the smaller sets.

On the 60 inch, which is quite a bit different the STB pin must be high for the backlights to come on at full current. The PWM signals will put the backlights in a soft start condition with STB low, but when STB goes high PWM signal goes from high to active adjusting the brightness. I guess the point here is that to force the backlights STB would need to be held high, but the dilemma then comes with what to do with SDA, SCL, and VCLK - just opening this thought for discussion.

Perhaps the LED controller has a datasheet, so maybe post a clear pic of the backside of the Power Supply and see if you can get the numbers off that IC, which is IC7201 an 80 pin IC. It might be a dead end if no datasheet exists, which is fairly common.

I suspect you have done it right but just to be sure when trying to enter the service menu you are starting with the TV unplugged and following the steps below:

Entering the adjustment process mode
1)Press and continue to hold the VOL v & INPUT buttons while plugging in AC power.
2)Continue to hold the VOL v & INPUT buttons until <K> appears on the top left side of the Display


Have you tried the reset with the latest board?

[c00lman]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

Tried to jump the power supply (bu5 and ps-on or bu5 and ps-on and pn-pow). But it does not activate or turn on the back light . The only way I can turn on the back light is via the force boot ch- and vol +.

Measuring from ground to led-k. L2 connectors
All pins are around 112 to 114 v.

From Leda and led k.
All pins are around 139 to 140v


Measuring the current on each strip (disconnecting it from the connector and putting the multi tester in series) I’m getting

Led1. 18.4 ma
Led2 18.3 ma
Led3 18.4ma
Led4 18.1ma to 18.3
Led5 18.3ma
Led6 17.9 - 18.2
Led7 17.9 -18.2
Led8 17.8
Led9 17.7 to 18
Led10 17.9 18.1
Led11 18.1
Led12 18.0
Led13 18.0 18.1. Sometimes to 19
Led14 17.7
Led15 17.9
Led16 17.8

Some of the led strips current is steady and some are ranging within .1 to .3 mA difference except for led13. It’s fluctuating sometimes up to 19mA. Not sure if it’s the connection or it does not really measure to anything hehehe

I will try to do some more measurements within the next days. It’s really hot �� lol

I think this one is beyond my electronics skills. Wish we have some schematics on this power supply or Sharp created the TV that you can check/replace the LED without dismantling this gigantic screen lol

Again, DO NOT touch both metal leads when measuring haha not fun
Let me know what you think

[c00lman]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

I will Try to redo the measurements lol. This time. I will put the plus to the L1 connector and negative on the L2 connector with corresponding pins.

I’m also thinking of measuring the current on each LED strip by putting the multimeter in series and hopefully will get different readings. I am assuming if there’s any shorts on the individual LED, the current consumption should go up a bit. I’m also assuming the LEDs are in series. Unless my theory is flawed lol hahaha

[budwich]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

As indicated, backlight testers are a "gross tool" for "quickly testing" backlights. However, most cannot provide the current demands that are used. Hence, if you have individual led issues, these may not be detected other than the system in the set that monitors the amount of current being used. Jumping the power board to turn it on should also turn on the backlights in most cases assuming that you have disconnected the main board (ie. you can't jump the pins and leave the cable connected). Your previous posted voltages seemed to indicate some difference therein.

edit: the OFL (pin 23) might need to be set.... but this is just a guess. there are posts in the forum for forcing backlights on somewhere.

[c00lman]

Re: Sharp LC-90LE745U 3 slow and 1 fast Blink

I will measure the voltage again when force boot.

The initial measurement I did is from gnd to the pins. Not from the pins + and -

Let you know