Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

[BenjaminJWD]

Hello,

I have been reading through a thread about another sharp that lead me to test quite a few different voltage outputs. I am reading 7.34 Volts from PO-1 and PO-2 (PNL12V). I just want to make sure I'm not crazy and that a bad power supply is probably what I'm dealing with.

I'm asking because I was a little surprised how steady at 7.34v DC the reading was for both PO-1 and PO-2. If anyone knows the specific diode, capacitor, etc, that could be causing this, I would much prefer to replace those rather than purchase a new power supply.

Also, I am having a difficult time finding a schematic for the Power Supply. Does anyone have access to that? (DPS-167CP, runtkb109wjqz)

Thanks!

-Benjamin

[budwich]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

disconnect the cables going from the tcon to the panel and see what the reading is there after.

[BenjaminJWD]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

disconnect the cables going from the tcon to the panel and see what the reading is there after.

I disconnected each of the two ribbon cables one at a time and tested voltage. It stayed steady at 7.34v on each disconnect. When I disconnected all connectors to the entire tcon it went to 7.35v. Disconnecting the LED power changed nothing, as expected (just extra caution).

Thanks!

-Benjamin

[BenjaminJWD]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

I also tested the voltage on the LED power. They were 1 - 83v.4, 2 - 86.0v, 3 - 85.0v, 4 - 83.4v (I measured with the connector disconnected at the positive pin (L1-1, L1-5, L1-9, L1-13) and at the capacitors. I don't know if this is useful as the Main Board is not kicking on the LEDs, but I thought I would add the information.

-Benjamin

[dskall]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

Your voltage for t-con may be routed through your mainboard. Are you getting 12v off your powerboard?

[BenjaminJWD]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

Your voltage for t-con may be routed through your mainboard. Are you getting 12v off your powerboard?

There are 4 pins (PO-1,2 and PO-3,4) that go directly to the tcon. According to the board, PO-1,2 are supposed to be PNL12V. Everything I'm reading about this board says it should be 12v, but I can't trace back far enough to find the 12v on the board. I can find the 13.2 in various places and obviously the 5v, but not 12v.

I have tested at the power board, and the tcon. Both provide 7.34v.

One of my problems being my multimeter was not meant for connectors this small and I may need to invest in one meant for small electronics.

I will also admit that I am only able to trace back 5 connections before I lose track on the PCB. I would love to find a schematic of this board, but so far no luck.

Thanks!

-Benjamin

[dskall]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

Should be able to trace back with ohmmeter and check components along the way with power off. Bottom side of board.

[budwich]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

there aren't many "published" schematics of powers. Most people on here "bear down" and trace back as far as possible. Based on a quick look at shopjimmy pictures, did you make it / trace back to q7120 (under the heat sink). It would appear that's where potentially the 12v originates... my "guess".... assuming of course that it gets by the FB at the start.
Of course, you are looking for the "7.3v" in your "meter tracing" as opposed to 12v which likely won't be anywhere... right?

further, it would appear that q7120 gets a "feed" from the UR13.2 "source" which you said is there.

[BenjaminJWD]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

there aren't many "published" schematics of powers. Most people on here "bear down" and trace back as far as possible. Based on a quick look at shopjimmy pictures, did you make it / trace back to q7120 (under the heat sink). It would appear that's where potentially the 12v originates... my "guess".... assuming of course that it gets by the FB at the start.
Of course, you are looking for the "7.3v" in your "meter tracing" as opposed to 12v which likely won't be anywhere... right?

further, it would appear that q7120 gets a "feed" from the UR13.2 "source" which you said is there.

Yes. I traced the 7.3v to under the heatsink, but didn't have a small enough clip to isolate only one pin of the four. And yes, the 13.2 was on the same 4 pin...actually, I don't know what it is called. But it has 4 pins and is connected to the heatsink.

I'll try to isolate each pin's voltage when I get home.

Thank you for the guidance!

-Benjamin

[BenjaminJWD]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

As an aside, I definitely do not know all of the terminology. I believe "isolate" has a specific definition in circuits that I may have just misused. Please forgive any misuse of terminology and just be blunt and let me know I'm saying something wrong.

I have done a lot of capacitor testing and replacements, to repair computer motherboards, dryers, HVAC, etc. I am learning how to troubleshoot bigger issues than a simple blown cap. However, I am definitely a hobbyist that is learning a new field.

Thank you, again, for your guidance.

-Benjamin

[BenjaminJWD]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

Of course, you are looking for the "7.3v" in your "meter tracing" as opposed to 12v which likely won't be anywhere... right?

further, it would appear that q7120 gets a "feed" from the UR13.2 "source" which you said is there.

Ok, I have attached two pictures that show what I believe to be the faulty voltage regulator. Is that what you were referring to with the q7120?

Is this an equivalent? Mouser Voltage Regulator

Thanks!

-Benjamin

[dskall]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

Need to read part number. Mouser ic pin1 is input, pin 2 should be 12vdc

[budwich]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

Ok, I have attached two pictures that show what I believe to be the faulty voltage regulator. Is that what you were referring to with the q7120?

Is this an equivalent? Mouser Voltage Regulator

Thanks!

-Benjamin

you actually need to read / measure all of the pins.... plus as suggested find out what the device actually is.

[BenjaminJWD]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

Need to read part number. Mouser ic pin1 is input, pin 2 should be 12vdc

Pin 3 seems to be ground (-00.2V). It breaks out to the screw on the corner of the board and down the center of the board to other grounds. Pin 4 (2.709V) is not so easy to trace. It seems to be heading to PD-16 (PNL-POW).

Thanks!

-Benjamin

P.S. I just realized I have been saying PO when it should be PD for all of the pins above.

[budm]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

https://www.badcaps.net/forum/showth...602#post592602
KIA378R12PI ?

[budwich]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

great hint!!!!! ^^^

You might want to buy a couple of them... as you potentially might have a panel problem that is taking them out. The panel maybe salvageable though it might take a bit of "testing" which may or may not blow that device.

[dskall]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

Is this your part number for Q7120 (KIA378R12PI)? If it is pin 2 should have 12v. Does it?

[BenjaminJWD]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

https://www.badcaps.net/forum/showth...602#post592602
KIA378R12PI ?

Thank you for the link! I searched google so much for different part numbers, I didn't even think to search the forums. My bad.

great hint!!!!! ^^^

You might want to buy a couple of them... as you potentially might have a panel problem that is taking them out. The panel maybe salvageable though it might take a bit of "testing" which may or may not blow that device.

Indeed. I usually order parts in 5s and 10s.

Is this your part number for Q7120 (KIA378R12PI)? If it is pin 2 should have 12v. Does it?

Pin 2 definitely is only supplying 7.34V, which it should be supplying 12V according to the board. I'll be pulling the heat sink and Q7120 tomorrow. I need to get a new wick. Once that is done, I should be able to verify.

Thank you, all!

Have a great night!

-Benjamin

[BenjaminJWD]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

https://www.badcaps.net/forum/showth...602#post592602
KIA378R12PI ?

budm, you were dead on with the part. The heat sink was slightly more annoying than I thought it would be, but it is out and that was the correct part number. I've ordered 10 ($0.88 each) of them and I'll update once I have installed.

Thanks, everyone!

-Benjamin

[BenjaminJWD]

Re: Sharp Aquos LC-60LE650U No Backlight 2 long 5 short

https://www.badcaps.net/forum/showth...602#post592602
KIA378R12PI ?

great hint!!!!! ^^^

You might want to buy a couple of them... as you potentially might have a panel problem that is taking them out. The panel maybe salvageable though it might take a bit of "testing" which may or may not blow that device.

Is this your part number for Q7120 (KIA378R12PI)? If it is pin 2 should have 12v. Does it?

Thanks for everyone's help. The TV is up and running. Time will tell, but I have 9 extra parts if it happens again.

I know for a fact that the TV was enclosed in a wood bezel with no ventilation in a conference room and I wonder if that may have been part of the problem.

Thanks, again!

-Benjamin