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Old 05-06-2019, 09:11 PM   #21
Davi.p
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

Hi, i think you're very lucky to get this tv for free if you will keep it for yourself, also because you don't seem to be much practical with theese, i have to spend thousand dollars to get a beast like this, and not with a basic fault like this! :-)

Any way..

1. The R7133 can't be 2,2ohm i guess, see it better, it is red red silver gold or red red silver silver.. (0,2 ohms)
2. There can be more damages tha what you expect, before R7133 you have to check the 2 big diodes and 2 big mosfets on heatsinks, then the white sense resistor R7217
3. The snubber diode D7112 is not a TVS and is clearly cooked watching its legs.
4. The IC is for sure cooked as the diode in parallel to the pins 4-GND makes you believe it's ok but if you desolder one leg of that diode besides the ic you will se an OL both ways in IC test.
5. The 4 SMD 1Mohm resistors may be bad, i think your meter must read them if them are good.
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Old 05-07-2019, 09:24 PM   #22
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

thanks budm. thats good to know. i already put it back in circuit, so idk if i will need to do that. hopefully not.
i ordered 5 resistors and 2 IC's
total cost 10.80 with 1st class shipping
i will post the results when they come in.
thanks for all your help!
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Don't fear the repair...
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Old 05-08-2019, 03:09 AM   #23
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

Davi.p sorry I didn't see your post till later. Thank you for your input. I guess I may have been a bit hasty in ordering parts. Hopefully I won't habe to order again. I tested r7217 and it has low resistance like a good fuse. Q7208 and q7209 test the same as q7202 and q7203. I'm not totally sure how to test these but in diode mode with black probe on drain I get .4 voltage drop to the source and 1.5 to the gate. Red probe on drain I get OL to both source and gate.

Im nor sure which 2 big diodes you mean before r7133 but I've checked just about every diode and resistor on this this board anywhere near the problem and they all seem fine except for r7133.

How do you know the snubber is not a tvs?
Also how would you test the mosfets?
Thank you for your advice. I am always looking for more things to check

And R7133 is most definitely red red gold gold. I have good eyes and I know the difference between silver and gold.

Oh and those 4 1meg resistors are testing at .85 mega ohm on my meter now. Not sure why I couldn't get a reading before. So I think those are probably ok.

Are you saying if I take away d7109 that I will read OL beteen pin 4 and pins 5,6,7,8?

Last edited by triplefour; 05-08-2019 at 03:19 AM..
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Old 05-08-2019, 06:04 AM   #24
Davi.p
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

The transistors are ok, the 2 diodes on heatsink D7217,D7218?

In almost every PSU shematic i've seen, there is not a tvs but a shottky or fast diode in the snubber, together usually with a condenser and a resistor.

Quote:
Are you saying if I take away d7109 that I will read OL beteen pin 4 and pins 5,6,7,8?
Yes
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Old 05-15-2019, 02:20 AM   #25
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

ok the parts finally came in and i got right to it. replaced the resistor, still no 5v, but resistor did not blow. replaced the IC and now i have 5v standby! success!?
not quite...
when i hooked up the mainboard i see the standby light flashing one long, one short, over and over.
(is this a code?)
the main filter caps stay at 175 and i still only have the 5v rail.
so of course i move to the next step. isolate the psu and try to turn on the PSU without the MB or backlights connected
i am able to trick the psu on using 1k resistor between BU5v and PS_ON pin.
it looks good. i get 400v on the main filter caps, i get the UR13V as well as the BU5V now.
so i go ahead and hook up the backlights and run another 1k resistor from 5vsb to PNL_POW
and i see the PNL12V voltages and i see 116v on all the pins at LED strip connector CN7601 (the anodes). i see 0v on all pins on CN7502. not sure if thats normal. dont fully understand the anode-cathode return LED stuff... but i do not see any backlights lighting up or even a flash
after all that i put everything back to normal one more time just to verify and yep its still doing the one long, one short flash...

what could it be? ive definitely made some major progress here. feels so close. someone help me seal the deal here please!
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Old 05-15-2019, 03:04 AM   #26
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

ok i found the factory reset thread and tried what tom66 said here
https://www.badcaps.net/forum/showpo...9&postcount=11


holding input + volume down as i plug in the TV got it to power up! backlights come up...but i get no picture on the screen. tom66 says im supposed to see a K somewhere on the side of the screen, and then push CH- and Vol- to get into service menu, but i see nothing. i tried it over and over with no success.

inching closer and closer... what can i try next?
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Old 05-15-2019, 04:13 AM   #27
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

Try pressing channel down and volume up buttons at the same time while plugging tv back in if you here a click, the tv has been reset.
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Old 05-15-2019, 04:20 AM   #28
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

try having it plugged in, hold power button in while unplugging and then plugging back in.
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Old 05-15-2019, 04:49 AM   #29
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

If your getting proper voltage going from powerboard to backlights, it looks like problem in backlight circuit, bad led/s or connections etc.

Last edited by nomoresonys; 05-15-2019 at 05:24 AM..
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Old 05-15-2019, 05:23 AM   #30
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

Could try
channel up and volume down.
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Old 05-15-2019, 05:52 AM   #31
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

Quote:
Originally Posted by triplefour View Post
ok i found the factory reset thread and tried what tom66 said here
https://www.badcaps.net/forum/showpo...9&postcount=11


holding input + volume down as i plug in the TV got it to power up! backlights come up...but i get no picture on the screen. tom66 says im supposed to see a K somewhere on the side of the screen, and then push CH- and Vol- to get into service menu, but i see nothing. i tried it over and over with no success.

inching closer and closer... what can i try next?
so you get this result with basically everything plugged in (ie. all cabling / cards), right? You indicate that you get backlighting... but what does the screen look like... white, black, grey?

You can try the same power sequence with one tcon to panel cable disconnected and see what get displayed... this set has 4 right... do the test with the two on the right disconnected and repeat with the same thing on the left.
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Old 05-15-2019, 12:35 PM   #32
Davi.p
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

Check the psu output connectors if you have an AC_DET signal and if it is high state.
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Old 05-15-2019, 03:43 PM   #33
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

idk what happened. i had it so close, but now something is wrong on the PSU again and i cant get the 13v to come back on even tho i put 5v to PS_ON.

after trying the resets (both styles) i had it where it would turn on normally, backlights come up, but no picture just a black backlit screen. never saw the K. never made it to service menu.

sometimes i was getting the 2 long 5 fast code.

i tried disconnecting each one, or both of the tcon cables. (there are only 2) the side disconnected gets a white screen. nothing special there.

i had my laptop hooked up and could change input until it was on the correct HDMI and i could hear sound but still no picture.

then suddenly while i was doing somethign with the laptop, the tv made some switching noises and turned off.
after that i couldnt even get the psu to do 5vsb. i was getting like 1v.
i let it rest a while and came back and got 5vsb again, so i tried turning it off and plugging everything in again, and i just get nothing. back to only getting 1v on the 5vsb pin.
so i left it alone for the night. tried it again in the morning. same thing.
so i suspected the IC had blown again or something. i took it out and tested it against the known good one (i ordered 2 for this reason)
and it seemed totally fine. resistance and diode checks between pins all come out the same. so i put it back in, and now i get a solid 5vsb every time, but nothing i do will bring the 13v back. plugged into the MB i get 2 short and 2 long flash code (never saw that one before)
tricking the psu with 5v to PSON gets me nowhere. the only other line besides the 5v that comes up is AC_DET which is at 3.2, which is the same reading i was getting when i had the 13v and 12v and everything.

so i figure something else has gone wrong on the PSU...

so i traced the PSON pin to where it goes...but im totally lost. dont even know what to call the things i see here.

the 4.6v i get from the PSON pin (due to 1k resistor between 5v and PSON, i dont get the full 5v...but this should be enough, right?)
goes thru C7520 and C7524 and into the top right leg of PC7101 which bridges the gap between the hot and cold sides of the PSU.

markings on it say:
R
2581A
WK 1.35
i have no idea what this part is or what it is supposed to do.
any explanation will be greatly appreciated.

out of the bottom right leg, i get 6.4 volts somehow (switching to negative leg of filter cap for ground ref)
which goes to the left leg of IC7101
which is another part im not too sure what it is or how it works. it says K A R above it.
markings say:
KIA
431A
145

it has 3 pins. i get 6.4 on the left, 0 in the middle, and 2.5 on the right.

after that, i kind of lost hope because there are just too many unknowns and i need help to understand which way current is going and what its actually doing.

what is supposed to happen to the ~5v PSON signal? i know its supposed to go back and tell the Hot side to crank up the juice in some way or another....

feeling a little sad cause i thought i was so close and now ive gone back a step
help! please
Attached Images
File Type: jpg PC7101.jpg (378.9 KB, 2 views)
File Type: jpg PC7101-back.jpg (148.6 KB, 1 views)

Last edited by triplefour; 05-15-2019 at 04:16 PM..
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Old 05-15-2019, 04:07 PM   #34
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

2 seconds on google and you would find 2581a = PS2581a photocoupler, It is used to isolate a signal from the the cold side to the hot side, Turning the led on or off on the cold side, causes the photo transistor on the hot side to conduct or not (switch on or off in this case)
On the hot side, kia431a is a reference ic, basically used in the power supply as a reference for regulation.

There is a fuse near that section you should check, it is labeled icp7201

Last edited by R_J; 05-15-2019 at 04:39 PM..
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Old 05-15-2019, 04:22 PM   #35
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

thanks for the explanation. sorry for not googling first! i looked for a fuse at ICP7201 but its just a jumper wire! what is happening to the 5v pson signal, and where does it need to go to turn on more power?

i googled 2581a but i dont see where it equals PS2591a photocoupler, i just get a bunch of links to datasheet sites with results on them that are almost close to what i have but have extra letters or numbers so how do i know im getting the right info? just assume theyre all basically the same? i dont know enough to assume those kinds of things

but reading the datasheet for PS2581AL1 , i seem to see that the LED is the bottom pins 1 and 2, and the transistor is the top pins 3 and 4.
out of the 4 optocouplers there, 3 of them are oriented one way which would seem to me to be a LED flashing on the cold side, telling a switch on the hot side to open and close. but the one of them that i was actually looking at is oriented the other way, seemingly a LED flashing on the hot side, telling a switch on the cold side to open and close. this is backwards from what i was thinking, if i was thinking that a signal from the PSON pin should go to the hot side and ask for more power... what am i missing here?

any chance of a schematic for this PSU existing?

Last edited by triplefour; 05-15-2019 at 04:46 PM..
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Old 05-15-2019, 04:42 PM   #36
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

That ps2591a was a typo, should have been PS2581a. The R is Renesas, the other numbers will be date codes etc.

Last edited by R_J; 05-15-2019 at 04:50 PM..
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Old 05-15-2019, 05:19 PM   #37
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

Change that snubber diode...
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Old 05-15-2019, 05:47 PM   #38
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

Quote:
Originally Posted by Davi.p View Post
Change that snubber diode...
i took the snubber diode out and tested it with my LED tester as budm said to do. i assume black lead on the side with the stripe. it went up to about 250 pretty quick, and then slowly to 251, even slower to 252..aaannnd even sloowwwwer to 253...

what does that tell us?
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Old 05-15-2019, 06:12 PM   #39
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

What component are you checking? If you have 5 volts standby, leave that circuit alone, it's working fine.
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Old 05-15-2019, 07:01 PM   #40
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Default Re: SHARP LC-80LE633U has open resistor r7133 on PSU

the TVS or Snubber diode labeled T3D1D at location D7112. davi.p insists i must replace it. budm said i can test it with a LED tester.

so if i have 5vsb, then this IC7102 and the area around it should be fine?
it doesnt do anything but provide that 5vsb?
why are all 4 of the source pins showing 0v?
i looked at the datasheet for a long time but it still isnt clear to me which way current is flowing, where its going, what its doing... it seems to say current can both come out of and flow into pin 2 which really confuses me...did i read that wrong?


and also when i trace the PS_ON 4.6v to the optocoupler, its not even going to the LED side of the optocoupler. everythings backwards and upside down in my mind right now

Last edited by triplefour; 05-15-2019 at 07:02 PM..
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