Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

[kca]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

Found a matching resistor. I have about six of the 2.2's actually, and they all read 2.4.

I think you're right, RJ. I can track down that IC tomorrow but wondering if there is any harm in switching out the bad one with a good resistor tonight? It will likely blow again, so I won't go ahead and do that if you think it might cause more damage to the PSU.

[R_J]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

You can likely check the ic for a short. Check between pin 4 (D) and any pin 5~8 (S) if there is a low resistance the ic is shorted.

[budm]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

you can likely check the ic for a short. Check between pin 4 (d) and any pin 5~8 (s) if there is a low resistance the ic is shorted.

+1.

[kca]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

Okay. So here's what I see when I checked for resistance between Pin 4 (top-right corner of the IC) and any of the bottom four pins (#'s 5 through 8):

With the red probe on #4 and the black on 5 through 8:

@ 200 = Meter reads 1
@ 2000 = Meter reads 1
@ 20K = 6.32
@ 200K= 07.2
@ 2000K = 007


With the black probe on #4 and the red on 5 through 8:

@ 200 = Meter reads 1
@ 2000 =707
@ 20K = 6.68
@ 200K= 07.4
@ 2000K = 007

Are those values low enough to confirm that the IC is indeed shorted and needs to be replaced?

and

Is there any other component(s) I should be testing / potentially replacing other than IC7102 and R7133 while I am at it? I can get up to a shop in San Jose tomorrow but it's about 30 minutes away so trying to get everything I might need in one trip.

And .... I took R7133 out of the board and noticed that even though I have several new resistors that match the same Red, Red, Gold, Gold (2.2 Ohm) pattern, they are not the same size. In the picture below, the fried one I took off the board is on top. and measures about 6 mm. The new one would be almost twice as big at about 11 mm. Can I use that physically larger one or should I pick up a few of the smaller, 6mm ones tomorrow that would be a perfect match for the original?

[kca]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

Sizings for R7133:

[kca]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

Thanks for all the help, guys. Feels like we're making alot of targeted progress and I appreciate all of your expertise.


~ kca

[budm]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

"Okay. So here's what I see when I checked for resistance between Pin 4 (top-right corner of the IC) and any of the bottom four pins (#'s 5 through 8):"

Look at the IC spec sheet and the IC on your board, pin 1 is marked with Black Triangle, then pin 2, pin 3 is cut off, pin 4 (D) is bottom left corner, pin 5 (S) is bottom right, then pin 6 (S), pin 7 (S), pin 8 (S) top right corner.

[kca]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

Sorry, I should have looked at the spec sheet before posting last night.

Okay, here are the values using the correct pins (going by budm's directions in combination with the spec sheet photos attached):

With the red probe on #4 and the black on 5 through 8:

@ 200 = Meter reads 1
@ 2000 = Meter reads 1
@ 20K = Meter reads 1
@ 200K= Meter reads 1
@ 2000K = Meter reads 1


With the black probe on #4 and the red on 5 through 8:

@ 200 = Meter reads 1
@ 2000 =455
@ 20K = 6.36
@ 200K= 34.9
@ 2000K = 235

[kca]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

Do those readings indicate that this IC should be replaced? Not sure if they are low enough to call for that or not.

[budm]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

The MOSFET side may have blown open circuit.
At this point I would replace the IC, order more than one in case you mess up during the installation/testing.

[kca]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

Okay. Will do.

Can I ask, budm, which of those last resistance readings I provided were informative? Was the 455 @ 2000 the most indicative or was it something else. Trying to learn for the next time I encounter something similar.

And, should I measure any other component on the board before making a run up to the electronics shop? Thanks in advance.


*****
One more question: The entire inscription on IC 7102 reads:


1132
TNY274PN
93477J

Do I only have to match the TNY274PN number, or when purchasing the new ones do I also have to match the 1132 and/or the 93477J as well?

[budm]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

Okay. Will do.

Can I ask, budm, which of those last resistance readings I provided were informative? Was the 455 @ 2000 the most indicative or was it something else. Trying to learn for the next time I encounter something similar.

And, should I measure any other component on the board before making a run up to the electronics shop? Thanks in advance.


*****
One more question: The entire inscription on IC 7102 reads:


1132
TNY274PN
93477J

Do I only have to match the TNY274PN number, or when purchasing the new ones do I also have to match the 1132 and/or the 93477J as well?

Your readings:
@ 200 = Meter reads 1
@ 2000 =455 = 455 Ohms
@ 20K = 6.36 = 6.36K Ohms
@ 200K= 34.9 = 34.9K Ohms
@ 2000K = 235 = 235K Ohms

We are looking for really low Ohm that causes too much current to flow through resistor blown the resistor.
Your Ohms readings are not consistent that it has range from 455 Ohms to 235K Ohms.

TNY274PN is the P/N, other numbers are date code/factory code.
Your meter reading is not real inclusive

[R_J]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

With the red probe on #4 and the black on 5 through 8:

@ 200 = Meter reads 1

If this means 1Ω between 4 & 5~8 the internal mosfet is shorted. Like budm said, get a couple in case there is another problem, but it is likely just the ic & resistor.

[kca]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

The 1 reading on the multimeter is not Ohms. I believe it means the same as OL. The attached picture is not of my multimeter, but the reading looks like that.


On a related note, I decided to put one of the 2.2 Ohm resistors I had into the board last night and test it. I did this even though the ones I had were physically larger than the original after reading it was safe to do so. Just a larger wattage.

The one I used was appx. 11 mm long (and therefore 1 watt) and the original was only 6.5 mm (and therefore 1/4 watt). I just want to make sure that it is okay to have used the larger one and to leave it in there going forward. Is that the case?


And .... I decided to plug in the tv and see if this 11mm (1 watt) resistor would blow or not and it held. It also held when, with the tv still plugged in, I hit the Power button on the side of the tv and it still held. However, there was no change in the non-operaitonal status of the tv ~ still no picture, no sound, and no LED standby indicator on the front of the tv itself. The 11mm (1 watt) resistor that I soldered into the board continues to measure 2.2 Ohms this morning .... just as it should.

Can I just leave that larger resistor in the R7133 leadholes? I can get the 6.5mm ones if I need to but I will have to order them and go through the wait time for its arrival.

[budm]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

The IC has blown open circuit basically.2
Higher Wattage will take higher current for the resistor to blow so more damage will occur.
Can't you get the same size as original?

[kca]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

Hello budm ~

The Digi-key website was giving me some problems with the ordering process, but I figured it out. Along with ordering 3 of the TNY274PN IC's I also picked up a 10-pack of the 1/4 watt 2.2 Ohm (red, red, gold, gold) resistors. So, they will be an exact match for the original R7133 resistor.

All of that should be here in 3-4 days.


~ kca

[R_J]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

R7133 is a 2.2 Ω 0.5watt (1/2 watt) not 1/4 watt

[kca]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

Hello RJ

I was going off several charts I found online that indicated an appx. 6.3mm length resistor equates to 1/4 way. And, the 1/2 watt size is appx 8.5 mm in length. If you take a look at the pictures I posted just above the small, original resistor is almost exactly 6.3 mm long.

Did you find something different on a specification sheet for R7133 on this board?

~ kca

Here's one of the websites I utilized:

https://www.electricalengineering.xy...-rating-chart/

And an attached pic from another site:

[kca]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

Well, felllas ......... got some very good news. I got the replacment parts yesterday (the IC and the resistor), carefully soldered both of them in and this 80" Sharp Aquos LC-80LE844U is up and running perfectly. Ordered an original remote control for it and once that arrives the operation will be complete. Can't thank you guys enough and would not have figured this out without you. As it turned out, the IC cost 90 cents and the resistor was less than a nickel. An 80" screen rejuvenated for less than a dollar. I call that a victory.

A couple of final notes that might help others in the future if they run into a similar or same problem:

1) Take very careful note of how the IC is soldered in before taking the problematic one out and replacing it. In this case, most of the pins need be soldered in a way that keeps each one independent, but two of them were tied together and then those same two were tied into two small, nearby resistors. See attached picture. You will need to duplicate that configuration exactly when you go to put the new IC into the board.

2) I'm pretty sure that the resistor we were discussing, R_J, ended up being a 1/4 watt (at just over 6 mm in length) and not the 1/2 watt which was about 8.5 mm). I ordered both but after matching them up with the original, defective one it became clear that the 1/4 watt version was indeed the correct match.

3) If you go to order a remote control for this particular Sharp tv, the original one hss the Part # of: GB118WJSA. There are plenty of somewhat cheaper replacement remotes (some of which look almost identical), but it is worth a few more dollars to get the OEM remote. See the attached picture for what this original remote looks like. Get it from a location in the good ol' US of A, too, because sometimes the overseas remotes may promote themselves as an original (and even have a photo of the original version), but when it finally arrives from China or elsewhere you can find out that they sent one of the less well designed and less functional replacement remotes instead.

Once again, I thank all of the posters who educated me in a patient manner and brought life back into this set. I'm going to be watching it for a few days before putting the back panel on and I'll report if anything changes. But, as for now, it has been running flawlessly for about 3 hours and looking mighty, mighty good! )

~ kca

[budm]

Re: Sharp Aquos 80" TV ~ Model # LC-80LE844U ~ Not operational

Thanks for the follow-up.