SHARP LC-80LE633U has open resistor r7133 on PSU

[R_J]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

I only mentioned how to work on the board out of the tv because in post #54 you seemed to be having trouble

whats the best way to read voltages on the underside of the board? soldering test wires is a pain.
can i safely run the board upside down, on a piece of cardboard, without any screws connecting it to a chassis?

Thats why I mentioned the resistors. And you don't need any chassis ground to work on the board, take it right out of the tv, all you need is the power cord.

[triplefour]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

ok but from experience you know that these optocouplers can and do go out? and sometimes heating them will make them work again for a bit?
totally worth checking if thats the case. hopefully all i gotta do is change out one of these (or all of em?) they seem like they must be cheap, or could i borrow some from another power supply? i know ive seen ones that look like these a bunch of times before, but would they have to be exactly the same numbers on top?

[budm]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

You can just short the Photo Transistor side (E and C) of the Opto together to simulate Opto on condition.

[R_J]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

I just had a closer look at this picture, I suspect the PSON opto is working, A quick way to tell for sure is check J7105 jumper, it should switch between 0 and 15 volts depending on the state of PSON
Based on the voltage on D7105, I believe that is the vcc that supplies ic7203
It could be that the power supply is working, check if you have UR13v

[triplefour]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

i dont have ur13v for sure. thats what im trying to get. i had it for a while after changing the ic and resistor but after trying to get to service menu and using laptop as a hdmi source, the tv shut off and i never got ur13v back. im not at home now so i will have to check that jumper when i get back.

budm thank you for your input. simplest solution is always best! i will definitely remember this tip and try it when i get home.

[budm]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

If PS-ON is OK, then it should have PFC Boosted Voltage on the main caps, if not then you need to fix that first.

[triplefour]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

PS_ON is not ok. i am only getting it by using a 1k resistor between 5vsb and PSON pin, and it is not boosting the PFC voltage so of course its also not producing the UR13v. think i need to short the phototransistor like you said and see what i get. ill get to it later tonight. but everyone will be asleep already!

so because the led normally would get fed with a constant 5v from 5vsb, switched by the PSON hitting the base of the transistor allowing the current to flow through the LED to ground, i can just short the phototransistor to achieve the same thing?

for some reason i was thinking the optocoupler would be using a rapid blinking LED to turn on and off the switch (phototransistor) very fast to control a duty cycle but maybe just overthinking it? do they work like that in other applications, just not here? ...because this is just a simple signal to tell the psu to boost the PFC voltage and turn on the secondary power IC?

[budm]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

You will be shorting the Photo transistor side just to see if the PFC will come on or not, if it does then we know for sure it is either Opto or the LED inside the Opto is not lit up to turn on the Photo transistor or not being driven on.
The Opto is either steady on or steady off in this PS-ON circuit, it is used as and isolation switch to control the circuit in the Hot side which is isolated from the cold side by the opto.
In typical setup for PS-ON, when OPTO is turned on, it will bias on a Transistor that is setup as switched linear regulator to supply the VCC for the PFC IC to run, and other IC's, the Voltage that is fed to the switched Transistor is from the standby power supply Aux winding of the Transformer.
So if you can get the P/N of the PFC IC then get the spec sheet so you can find out which pin is the VCC pin then you can check to see if the VCC is present or not when the PS-ON is present, that how you usually check first, find out if the IC has VCC for it to run or not.
See example of the typical topology used in typical power supply, study it to see how PS-ON, OPTO, Transistors are being used to supply VCC to PFC IC and other IC's, once you understand this then you can easily troubleshoot 100's of typical TV power supplies and many other power supplies as well out there, the trick is to understand how it works.
Hopefully the OPTO that you are checking is the one for the PS-ON.

[triplefour]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

thank you budm. yes i really want to understand it this time. i am tired of replacing boards. but for the customer this is usually the quicker option. i want to replace components! fix all the tvs! keep em out of the land fill. thats the goal!

[triplefour]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

davi.p i tested the psu with both the PSON pin to 5v and the PNL_POW to 5v as well, before i hooked it up to everything and had the backlight come on and and almost functioning tv except yes no picture just black backlit screen. but my point is this. during doing that testing, i saw that just putting 5v to pson, got me the ur13v. it was not depended on also having pnl_pow fed 5v. but i have tried that as well, and it doesnt change anything. pson at 5v should be enough to turn on the ur13v. pnl_pwr turns on the tcon...and LEDS, maybe?

i wish i had taken more notes while it was in that state but i thought i was so close!

and yeah... i do repair tvs professionally. ive saved a lot of them from the landfill. maybe check your ego a little bit eh? we all should be focused on the same goal here right? no hard feelings. thanks for your input. lets just chill and get to the bottom of this thing! <3

[triplefour]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

trying to follow what davi.p said, i see that the datasheet for the optocoupler does agree that 1.2 is a typical forward voltage for the LED. so really, reading 1.1v there means at least the LED side of the optocoupler seems fine. my meter is not perfect, so a difference of .1v is negligible. and reading 0 on the cathode side (pin2) would make sense, because its just going straight to ground after the cathode? please clarify me if im thinking wrong here.

this is where i get lost though. how should i know what to expect on the phototransistor side of the opto? the LED is just turning on a switch, and according to my voltage readings i made a picture of, im getting 17.2v on both of those pins, consistent with a switch being turned on allowing a current to flow....so maybe the problem is after that 17v...where does it go, and where does it not get to that it needs to?

[Davi.p]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

I don't wanna offend anybody, since you talked about customers it seemed you're a professional, but in the previous post you seemed familiar with electronics but since you dont know optocouplers i thought you were only hobbist like me, its only curiosity, my ego is surely not high usually, its nomoresonys that's malicious, the important thing is the tv, i think that without a schematic you will lost hours of study, pnl_pwr switches on only the tcon/panel not leds, if you cut te leg of the kia regulator that gets the 13v input you can test the 13v and if not present you can always resolder legs halves togheter. The opto output is already switched on..

[R_J]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

From your picture the 17 volts (which is produced by the standby circuit) IS getting to the optocoupler and IS getting to the Q7101. this transistor, switches the 17 volts which gets zenered to 15volts that supplies the vcc to ic7203 (main drive ic) and I believe it also supplies vcc for ic7201 (pfc ic)
Can you supply the number for ic7203?

Just a note on panel power, don't worry about that now, it takes ur13 volts and via a 12 volt 4 pin regulator (which has on/off control) supplies the panel 12 volts

[budm]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

At this point did you the P/N of the PFC IC and look up the spec sheet to identify the VCC pin of the PFC IC as suggested?
Need to get boosted PFC working first otherwise the power supplies that require boosted Voltage will not be working.

[Topcat]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

everyone go to a neutral corner and breathe into a paper bag....I have better things to do than play referee for the bickering. If you can't be of any assistance to the topic at hand, simply don't post....we don't care about opinions, especially regarding whether someone is a professional or not.

[triplefour]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

sorry for the delay. as usual life gets in the way! but here are the IC's

IC7203
SSC9512S
SK102
862T

[budm]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

IC7201: UCC28061 PFC IC
https://cdn.badcaps-static.com/pdfs/...fc433d57cd.pdf

[petehall347]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

everyone go to a neutral corner and breathe into a paper bag....I have better things to do than play referee for the bickering. If you can't be of any assistance to the topic at hand, simply don't post....we don't care about opinions, especially regarding whether someone is a professional or not.

well said . we are all learning regardless of titles .

[budm]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

well said . We are all learning regardless of titles .

+1000.

[triplefour]

Re: SHARP LC-80LE633U has open resistor r7133 on PSU

so the datasheet i posted for IC7203 doesnt really help me. because in the datasheet where it shows what pins are what, it is talking about the 16pin package. (SSC9512) then it says SSC9512S(SOP-18) is different
pin number.
SSC9512S is the IC i have on this board, and it has 18 pins....how can they just say "is different pin number" but not have another diagram showing the pinout? i looked around and this is the only datasheet i can find. how do i proceed?