Re: Sharp LC-45GX6U wont power on



Excellent suggestion! I have been using the actual power button on the set itself to rule out any IR/remote problems. But based on your experience can you tell which pin I need to monitor for a voltage that is supposed to be sent to the microprocessor to turn the tv on?

Looking at IC2203 there are quite a few possible candidates:

TV_POW
TV_POW2
STBY_POW
PANELPOW
SMPOW
DDC_POW


I am thinking it is STBY_POW from trying to follow it though. So I should...

Re: Sharp LC-45GX6U wont power on



Haha, thanks



Yeah it's going to hit 5 years this month. Is there any way I could rule out some of the other components, like the inverter boards for example? I suppose if an inverter board has a problem it could be causing the microprocessor to stay in this error state as well. I wonder how it would response if I unplugged them all... but then, would a perfectly working tv go into the same error state if it detects the inverter boards are not plugged in? I suppose so but a different error code (different...

Re: Sharp LC-45GX6U wont power on



Good day PlainBill!

Thanks for replying.

Yeah that would definitely make the most sense, it's just that I am not sure how to determine if stated voltage in the service manuals schematics are supposed to be constant or only when the unit is actually powered up.

For example on this DC/DC board the schematic shows that for plug P1702 pins 1-4 carry 12V. But if I tested it now they are all zero because the TV is not actually asking for that power from the power supply. It's not getting to...

Re: Sharp LC-45GX6U wont power on

wow didn't have any time to look at my tv for quite a few days now. Tonight I spent 15 minutes on the power supply unit. I learned how to trip the switch to the power supply by connecting two contacts so it outputs full power to all its pins as if the TV turned on. All the pins tested ok - 4 plugs 15V an 4 12V just as described in the schematics show. so I think its safe to say the power supply unit is fine, no?

That leaves two possible culprits in my opinion: the dc/dc converter and the top controller.

the top controller...

Re: Sharp LC-45GX6U wont power on

Thanks for the information PlainBill!

I am a bit stumped now at what to do. I realized couple days ago that I was looking in the wrong part of the manual for troubleshooting power problems - I was looking in the section for the external AVC box!

But the section for the TV itself is terrible. Its a short brief section for "Power supply error" and goes like this:

1. When turning on the power, pin (19) of IC2203 remains 3.3V.

Yes? Check IC4804 and its peripheral circuits.

No?...

Re: Sharp LC-45GX6U wont power on

Can anyone help me with some terminology from the service manual?

for example it mentioned testing specified voltage at: "S-Vcc+15V (pins (11) and (12) of PA/P1752)"

I can find the plug labelled P1752 but what does the "PA" in front refer to? I can find the pins 11 and 12 on this plug but does that mean I test the voltage by putting one contact on one pin and the other contact on the other pin or that BOTH pins should be 15V? I usually test voltages by putting one contact on what I want to test and...

Re: Sharp LC-45GX6U wont power on

Update- I did find the schematics diagrams and service manual online for free. I checked them out and I was following instructions in the troubleshooting section for "no power-up" where front LED does not change from red to blue. I got to the point where I am testing voltages at plug P1701 and P1702 and it's not matching what they specify - On P1701 I only see pin 6 with 6V, pin 11 with 2.5V and pin 12 with 2.4V. No discernible voltages in any other pin. According to this flowchart in the service manual, should be 1.8V at pin 6, 3.3V pins...

My Television just has a red light under "POWER" which blinks every 4-5 seconds. No other lights. If I try to turn on the power either via remote or the button on the television itself there is no response. Just the same blinking red light.

I opened up my TV and I visually inspected the exposed circuit boards. I see no sign of leaking, bulging or otherwise deformed capacitors. I also looked at the fuses particularly the fuse which is on the same circuit board the power cable plugs into and it is fine.

I would like to next plug the power in and test voltages...