Sharp LC-60E79U problems

[Redrebel10]

Hello all, this tv wont power on. When I push power the light power led stays on 2 or 3 seconds then I hear a clicking noise from power supply board then the trouble codes flash (power light and ops flash together twice then the opc light flashes 3 times). If I test volts on initial power up everything reads normal until the clicking noise then they drop to zero, however the 12v pins to tcon board only read .6v when powering up. I can start the unit with hard reset by plugging AC in while holding down the vol down and input buttons and this will power up all the backlight and it no longer flashes trouble codes. I still can't use the tv in this state or get anything to pull up on the screen, when I do this all the volts hold accurate except the 2 12v pins going to the tcon board, they read .7v when I do this. The manual suggests its the power supply board according to the number of flashes but I want to make sure I'm not missing anything before ordering a power supply board.
Thanks in advance, I'm new to this site but I'm very impressed and have learned a good bit from the members.

[attainteddragon]

Re: Sharp LC-60E79U problems

pictures would be great.

if you disconnect the t-con from the main (lvds cable), does the 12 stabilise, or is it still low?

[Redrebel10]

Re: Sharp LC-60E79U problems

I can test voltage in the morning, with tcon disconnected from main, if the voltage goes up to 12, which board is to blame for the problem?

[Redrebel10]

Re: Sharp LC-60E79U problems

Here is the picture of everything

[dick_barton]

Re: Sharp LC-60E79U problems

What's the part number on IC1101 on the underside of the main board?

[budm]

Re: Sharp LC-60E79U problems

What is the DCV on the PNL-PWR command pin/
What do you get on PNL-12V if that power cable to the T-CON is connected?
Switched MOSFET Q7120 provides the switched PNL-12V.
http://www.shopjimmy.com/sharp-rdenc...pply-unit.htm#
Sharp RDENCA369WJQZ (DPS-343AP A, 2950244303) Power Supply Unit
Pictures provided by shopjimmy.

[Redrebel10]

Re: Sharp LC-60E79U problems

Attaintedragon, the voltage does not change when disconnected tcon from main (lvds)

Dick, C18 lt bux is on IC1101

Bud, the DCV on PNL-PWR was .8 then dropped when the power board clicked and shut down, when I did the hold vol down and input start up, it reads a steady 3.2v. I only get .7v on the 2 PNL-12v pins going to TCON

thank you guys for all your help

[Redrebel10]

Re: Sharp LC-60E79U problems

Where is the MOSFET q7120 located? Is there a way to test if its functioning correctly?

[budm]

Re: Sharp LC-60E79U problems

It is mounted on the heat sink. So did test the pnl-12V without the cable going to the T-CON board?

[Redrebel10]

Re: Sharp LC-60E79U problems

when testing the pnl-12v, (in the force start up mode which lights all the backlights) it reads .7v, I can unplug that cable at the TCON board and voltage drops to zero

[budm]

Re: Sharp LC-60E79U problems

I cannot see how it drops to 0V on the PNL-12V pin unless there is no Voltage coming out from the PNL-12V.
At this point you need to report the Voltage reading on all 3 pin of the MOSFET when TV is off and when the TV is switched on.

[Redrebel10]

Re: Sharp LC-60E79U problems

Just to clarify that was with me testing the pin on the power supply board then unplugging that cable on the tcon side

Sorry for my lack of knowledge I'm slowly learning more but can you please inform me of where to check the Mosfet 3 pins I'm attaching a picture of the psb

[Redrebel10]

Re: Sharp LC-60E79U problems

All the Mosfet that start with q are on the primary side of the board, none of which are q7120 the 2 in the picture I'm attaching are q7602 and q7601

[budm]

Re: Sharp LC-60E79U problems

https://www.badcaps.net/forum/attach...9&d=1500513935
Left heatsink just above bottom left edge of the board, it is in the cold side of the circuit due to fact that it provides 12V for the T-CON.

[Redrebel10]

Re: Sharp LC-60E79U problems

can you zoom in on the picture I posted and give me the q number of the one you are referring to? Thanks

[budm]

Re: Sharp LC-60E79U problems

Do you see R7305, R7304, C7120?

[Redrebel10]

Re: Sharp LC-60E79U problems

Bud if I'm correct there are multiple mosfets I regret to inform you I'm not sure which one you want me to test

[budm]

Re: Sharp LC-60E79U problems

Look for those resistors and cap and you will see Q7120, I do not have the time to start the paint program to edit the picture right now.

[Redrebel10]

Re: Sharp LC-60E79U problems

yes I see them, the R almost look like diodes and the C7120 is a cap all on the secondary side

[Redrebel10]

Re: Sharp LC-60E79U problems

found it thanks to your tips, Ill test with power off and while powering on Thanks again