Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

[rted]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

Hi Budm, sorry if I don't follow your instructions. I also appreciate your patience and understanding.

I noted the 12V is coming from Q7120, Attached is a picture of the Q7120 from my previous post that looks like it has heat stress marks on the board. What do you think?

I also took readings of the Q7120 from the top side see attachment. I took reading from jumper J7058 and it was .13V.

Voltage reading at the PD pin 16 is .13V. Pin 15 is 4.95V all other pins are 0V. see pic PD connector voltage readings.

I hope this helps and again I'm doing my best and sorry if I mess things up.

RT

[budm]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

OK, so the main board is not sending the signal to turn on the electronics switch Q7120.
So troubleshooting the main board will be next.
You can do the following, you can force on the Q7120, or jump the input-output pin of Q7120 just to verify that the T-CON is OK, The key is that they must be done AFTER the TV is turned on.

[rted]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

OK, I jumped the Q7120 input output pins as you suggested after the TV was turned on and the panel power came on saw the screen turn on for about 3 seconds then went black.

I hope this was what you were asking for.

RT

[budm]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

Yes, so the error went away?
I wonder if the it goes back to standby due to no video signal detect or it has more problems.
Try to see if you can get on screen setup menu to come up.

[rted]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

The setup menu comes on panel picture looks fine. Do you want me to do a factory reset?

[rted]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

The error went away and the TV picture is fine. It's been on for almost an hour. I think you go it narrowed down now, great job!!!!!!

FYI Voltage reading on pin 16 is 10.8 Vdc. On the main board D3303 red diode blinking on /off. Turned TV off then on a couple times and the TV is working fine!!

[rted]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

The error went away and the TV picture is fine. It's been on for almost an hour. I think you go it narrowed down now, thank you!!!!!!

FYI Voltage reading on pin 16 is 10.8 Vdc. On the main board D3303 red diode blinking on /off. Turned TV off then on a couple times and the TV is working fine!!

.

[rted]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

This morning I turned the TV on by jumping Q7120 input/output pins and the TV picture was fine once again. Looking forward to finding the root cause of the main board panel switch not working.

Thanks again Budm for helping me get to this point.

[budm]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

Need to look at the diagram of the main board to see how that PNL-PWR is generated, there should be a switched transistor that is commanded on and off by the processor.

[rted]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

Looking forward to the solution. Thanks for everything to date.

RT.

[budm]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

Please check the resistance of the PNL-PWR pin (the control pin) against chassis GND for me, no power to the TV of course.
I just want to make sure it is not being grounded out.

[rted]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

Hi Budm, checked the resistance from panel power pin 16 to chassis ground. meter reads 1, open circuit.

Thanks,

RT.

[budm]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

OK, that is fine.
I look at the service manual which does not have any diagrams, just the block diagrams, the PNL-PWR seems to be generated directly by the processor without any buffer circuit.
So at this point you just have to use it the way it is, the only bad thing is that when TV goes into standby (not powered off by the power switch) when it does not detect video signal, the T-CON will still get 12VDC which is no big deal since the TV signal will always be present any way, otherwise the 12V will be shutoff when TV is turned off.

[rted]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

What do you think if I connect a push button switch to the input and output pins of Q7120, wire it so I can access the switch on the outside of the TV.

[newtothis]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

What do you think if I connect a push button switch to the input and output pins of Q7120, wire it so I can access the switch on the outside of the TV.

That would work

[budm]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

You can disconnect the PNL-PWR wire going back to the main board and then use 1K resistor with one end connected to STBY power supply, another end goes to the switch Common contact, The N.O. contact of the switch goes to the PNL-PWR pin of the connector PD of the power supply board.
This way you do not have 12V running to the out side of the TV, using low level signal is a lot safer.
Since one end of the resistor is directly connected to the STBY power supply, the other end goes to out side, so if that wire shorted to the chassis, the maximum current will be only 5V/1000 Ohms = 5mA.

[rted]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

Thank you Dudm, Newtothis, Johnboy1313, and R_J. I truly appreciate your patience, understanding and taking time to help me solve the problem.

As a doityourselfer sites like this are priceless, I'm going to make a donation and hope all other Newbies do the same.

Cheers to all!!!!

[bryan4203]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

OK, so the main board is not sending the signal to turn on the electronics switch Q7120.
So troubleshooting the main board will be next.
You can do the following, you can force on the Q7120, or jump the input-output pin of Q7120 just to verify that the T-CON is OK, The key is that they must be done AFTER the TV is turned on.

Im a total noob, and I know this thread is old, but how do i do this? Ive found q7120 and it has 4 legs. My question is where is the input-output pin? Thanks for reading

[rted]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

Did you ever get a reply or help with regards to my post " Sharp Aquos LC-70LE732U Blinking Pattern 2 -5"?

[rted]

Re: Sharp Aquos LC-70LE732U Blinking Pattern 2 -5

OK, I trace out the bottom side of the power supply board to see how the PNL-POW and the PNL12V are connected and generated.
As you can see, you can put the meter on JUMPER J7058 to test the PNL-POW signal.

The PNL12V output is from the electronics switch that is turned on by the PNL-POW signal.

POWER SUPPLY BOARD PD connector pinout:
PD-1-2 = PNL12V
PD-3-4-9-10-11-12 = SGND
PD-5-6-7-8 = UR13.2V
PD-13 = AC-DET
PD-14 =PS-ON
PD-15 = BU5V
PD-16 = PNL-POW
PD-17-18-20 = N.C.
PD-19 = DIMMER
PD-21 = OFL
PD-22 = ERROR
PD-23 = NOT USED
PD-24 = STB

Hi BUD M,

You helped me solve a problem with the subject title over a year ago. The TV has now gone to the blinking pattern 2 - 5 once again. I would like to replace the Q7120.

Would you be so kind to send me the part number of Q7120 or tell me where I can find the schematic so I can replace it on the board.

Your kind reply is greatly appreciated.

RT