Aquos LC-C5255U

[budwich]

Re: Aquos LC-C5255U

IF you have done things correctly both in terms of "statement" and "procedure" (that's a big IF... :-) ), it would appear that you have lost the 12v supply in the power supply....

You can check things further by disconnecting the 4 pin cable going to the tcon (from the power supply) and repeat the power up test and measure the output on the now disconnected cable at the appropriate pin in the cable connector. This test will help to see if you have some form of "loading" on the 12v supply coming from the tcon / panel. Go from there.

[budm]

Re: Aquos LC-C5255U

If you disconnect the T-CON and monitor the PNL12v and still do not have PNL12V then more likely the IC7121 is bad.
Sharp RDENCA295WJQZ (DPS-277BPA) PS.
What is the P/N as printed on the IC7121 (Switched 12V LDO regulator).
KIA??????
Pictures provided by shopjimmy.

[Techboxcomputer]

Re: Aquos LC-C5255U

I want to thank you both for hanging in there with me I know I have frustrated you guys and I appreciate the help I will print this and take notes today. THANKS

[budm]

Re: Aquos LC-C5255U

And what I mean by 'Disconnecting the T-CON' is that you disconnect that small connector that supplies the PNL12V to the T-CON board.

[Techboxcomputer]

Re: Aquos LC-C5255U

OK here are the results. With the 4 pin disconnected from the TCON I measured the voltage on the TCON end of that cable on the PNL 12v line I have .3v , it stays there until I hear the click and then spikes up to about 11.6 and then drains to zero. The IC 7121 is a Sharp PQ30RV31 29h W2 Thank-you

[budm]

Re: Aquos LC-C5255U

Do the EXACT same test with cable connected back in place and give us the result.

[budwich]

Re: Aquos LC-C5255U

OK here are the results. With the 4 pin disconnected from the TCON I measured the voltage on the TCON end of that cable on the PNL 12v line I have .3v , it stays there until I hear the click and then spikes up to about 11.6 and then drains to zero. The IC 7121 is a Sharp PQ30RV31 29h W2 Thank-you

:-( no looking so good. My guess is you have a panel issue which is pulling down the 12v supply. You might want to check some of the capacitors on the edge boards at the bottom of the panel. You might get lucky and find a "weak one" that is replaceable "in set"... maybe.

[Techboxcomputer]

Re: Aquos LC-C5255U

Do the EXACT same test with cable connected back in place and give us the result.

Doing the same test with cable reconnected to the TCON and measuring on the TCON end basically the same result. .3v until it clicks then spikes to 11.7 and rapidly drains Thanks

[budm]

Re: Aquos LC-C5255U

So let me get this straight:
So you turn on the TV, you can hear the click and the PNL12V jumps up from 0.3V to 12V and then it drops back down to 0.3V again, correct?
It does this with and without the T-CON connected.

[Techboxcomputer]

Re: Aquos LC-C5255U

Hi - I'll address that question first thing on Monday when I am back in front of the set. One thing that has been bugging me i would like to know. Why will the backlights come on when I force it into bipass or service mode? I don't quite understand that, especially if it was a power board issue feeding the TCOn why would it work differently when in either mode. Thanks again

[Techboxcomputer]

Re: Aquos LC-C5255U

Good Morning - I have redone the test above. I plugged in the TV, inserted my multimeter into the TCON end of that 4 pin wire where the PNL 12v feeds. I press the power button. The power rises to .3v, the TV clicks on it's own, the power spikes to 11.6 or so and then rapidly drains.

Thanks

[budwich]

Re: Aquos LC-C5255U

so whether the power to tcon cable is connected to the tcon or not, the voltage "response" / characteristic is the same.... at power plugged in, you see about .3v, then with power switched on / activated, you get a click and see 12v then it goes to 0v shortly thereafter.... flashing code ???? :-( please confirm the code flashing with the power cable connected and disconnected test (ie. no code, same code, different code).

Highly likely a panel fault but not totally sure. Can you retest the tcon to panel cable disconnect test? (ie. disconnect one cable from the tcon to panel, power up, what happens on the display / flashing code). Do same with the other cable.

Finally, look / provided pictures of the lower edge board of the panel. Some have found cap issues there that might be "on-set repairable". There are at least two lower edge boards so you can compare "looks" and measurements if need be.

[Techboxcomputer]

Re: Aquos LC-C5255U

Good Morning -
so whether the power to tcon cable is connected to the tcon or not, the voltage "response" / characteristic is the same.... at power plugged in, you see about .3v, then with power switched on / activated, you get a click and see 12v then it goes to 0v shortly thereafter.... flashing code ???? :-( please confirm the code flashing with the power cable connected and disconnected test (ie. no code, same code, different code).
OK - with the AC cable plugged into the tv, but the TV not switched on I get no voltage at all on the line that feeds the TCON. When I push the power button to turn on I get a read of .3v for about 60 to 90 seconds and then I hear the click, then the power spikes to 11.4v and drains to zero. Same effect whether the cable is connected to the TCON or not.
The blink pattern is the same with or without the TCON connected. I get one light that blinks 3 times and then 2 lights that blink twice together and then cycles again continuously doing a 3-2 blink.(I thought I read long ago this was a 12v error blink) With the other cable disconnected from the main board I see the same reaction and blink pattern also. (disconnected both and saw the same) I will point out this, after pressing the power on the one light is solid green until the click occurs, then the blink pattern comes on.

As far as the caps you would like me to check, I am assuming on the bottom of the power panel where I see about 4 blue capacitors I will try to check. I have a cap checker I bought years ago I am not totally familiar with I can use. Plus I bought a fluke 113 over the weekend in hopes of making some of this easier.

Thanks again.

[budm]

Re: Aquos LC-C5255U

OK: in your first post:
'I need a opinion. I have this Sharp TV that will not power up and has the 5 and 2 blinking light."
And now you are saying "The blink pattern is the same with or without the TCON connected. I get one light that blinks 3 times and then 2 lights that blink twice together and then cycles again continuously doing a 3-2 blink.(I thought I read long ago this was a 12v error blink)"

You have Power LED and OPC LED, correct? so please look again as to exactly which is which are blinking and how many times.
Bad data makes it hard to locate the problem.

[Techboxcomputer]

Re: Aquos LC-C5255U

I apologize and I will strive to be more precise.

OPC Blinks three times

OPC and power blinks twice together

Cycle repeats

[Techboxcomputer]

Re: Aquos LC-C5255U

While waiting on further instruction I pulled 4 caps from the bottom of the board. If I understand what they are they would be referred to as ceramic disk capacitors and I am assuming that is what you wanted checked. I measured all 4 with my Fluke and got open line both ways on the leads. Thanks

[Techboxcomputer]

Re: Aquos LC-C5255U

Update:

Found and purchased power board for this TV and installed it. Still no luck.
Blink pattern power and OPC twice, power 3 times. It does seem to stay powered for longer than before. I count 30 seconds between pressing power switch and hear it clicking off. I have not measured any voltages yet as this is supposed to be a working board from a damaged set.

[budwich]

Re: Aquos LC-C5255U

ok... probably a dumb question but is your "new report" of flash codes the same as what started the thread but was just reported "wrong" at the start, OR they have now changed to this after what is happening now?

[budwich]

Re: Aquos LC-C5255U

IF I understand correctly, your current "situation" is that you are in (power led flashes twice... opc flashes) mode... which then with 3 opc flashes, indicates an issue with the 5v powering "domain". So you need to check where and what that is pertaining to in terms of the system (ie. what board, chip, or otherwise).

[Techboxcomputer]

Re: Aquos LC-C5255U

OK Bud - I do believe it is the same exact flash code as we started with, 3 blinks from the OPC then 2 blinks from both the OPC and power lights. The seller has been trying to be helpful and suggests I check the fuse on the Tcon, but I am not sure what he is referring too.