Sharp LC-46DH77S Communication error? Bad main board?

[joens]

Hello.

I'm new here and read a couple of treads for tips but I cant find anyone who have my problem.
I'm from Sweden so English isn't my first langue...

I got the tv yesterday from a working colleage and it has been at a servicefirm but they couldn't fix it. They said that it was wrong on the main board, I'm not sure thats the case and was wondering if anyone here would like to help me find the broken part.

At startup the power-LED is onGreen), after about 2-3minutes it starts to blink. When pressing "menu" on the remote the OPC-LED blinks at t he same time as the power-LED.

What I can se in the servicemanual it has some kind of communication error.

I read here that the power-LED should be RED when the TV is off and GREEN when the TV is on. But it's just green or off. It never turns red.
It blinks oreange then updating the tv for a couple of minutes and then directly goes to a stable green light. I find that strange becouse the servicemanual says that the Power green/OPC flash alternately after the upgrade i succeeded and Green/REd when it has failed.

But anyhow, I was struggling with the upgrade yesterday and after upgrading i without a USB-stick in the USB-port the TV started up. It took quite long time from when the backlight started til the picture came up.
Then when it was ok I could turn it of off and on by pressing on the set without anu problem. Plugged in the blu-ray and wathed "lion King" for about 25min.
Then assebled the tv and dissconnected the AC-plugg. After I was finished it didnt start up again.
Later on the evening it started up again.

But most times the power and OPC flashes simoultainously, no extra blinks on the OPC and the both just blinks green.

I was thinging of mesaure the low DC-voltage to se if they all are there and they are correct.

Anyone had a problem like this?

The main board is quite hard to find in EU, called DUNTKE685WE and KE685WE25 Version 1.08(or now if the upgrade is ok 1.11).

[joens]

Re: Sharp LC-46DH77S Communication error? Bad main board?

Quick mesure and the only abnormal thing I found (I think) is that the BU5V(in the PD1(EU) connector) between the main board and the PSU only is 3,1v DC... Called P9601 on the main board.

There are one LED on the main bord blinking near IC2003 called D2002 (hard to see there are soldering point in the way)

One time when I got the TV started the two other Leds D9101 and D9102 were flashing also.

Found a main board in the UK. REady to order but I'm not sure...

[joens]

Re: Sharp LC-46DH77S Communication error? Bad main board?

Yesterday night I was looking at this again.
Were looking more for de low DC-voltages.

BU5V 4,9v
12V and 60V to the inverterboard ok.
pnl_pow 3,1v
ps:on 3,1v

The thing I didnt get understanding on was the "VON" to the invertercard.
It looks like there is about 2,1v but when I plug it in it dissapears. The only 2,1 on the connector to the inverterboard that keeps being there is REg2(or something like that).

Could it be the inverterboard? All other voltage seems ok.

When I plug it in it klicks one time and the power-led is steady on, on the main board the lowest led flashes and the highest one have a veak light. After a wile it reboots and after about 5 times the power-led starts to flash and all the voltages dissaperas exept for the PNL, PS an BU5V.

[joens]

Re: Sharp LC-46DH77S Communication error? Bad main board?

Very strange.

Today I work from my home and every time the power-led started to flash I pressed the stb-botton on the remote.

Then it started as nothing ever happend, after at couple of tries then. . .

When I mesure on the STB to the inverter board there is about 3,28v DC. Everyting is ok.

Must be that the main board dont send the correct voltage to the inverter board.

Order one today, wait a couple of days then we will se.

Even the fact that nobody answered this thread I had a lot of help from this side and I hope that if anyone else have the same problem this thread will help them.

Will update the thread after changing the main board. (with is flashing red and green like the most beutiful christmas tree ever.)

The clock is 09:10 local time here så it's not the middle of the night

[branislav18]

Re: Sharp LC-46DH77S Communication error? Bad main board?

Hi joens
I have Aquos LC-32DH77E with same mainboard duntke685WE and inverter board runtka456wjqz and have the same problem. Measure same voltages and same d2002 blinking.
Didn't solove problem yet.

[joens]

Re: Sharp LC-46DH77S Communication error? Bad main board?

Hello.

I forgot this thread but got an email now when it got answered

I bought a used duntke685 mainboard with all the same numbers.
it seems like they use the same board for many screens but ut has to be the same number, the one that isnt duntke685.

But anyway, got the card, changed the card, started screen. worked directly and still works.


payed about 600SEK or $100

so if you have the same problem, the main board is my tip.

[branislav18]

Re: Sharp LC-46DH77S Communication error? Bad main board?

Changing the mainboard will be the last option, I will try to repair it on the chip level. Thank you, your answer helps to focus on this board. I started to think that the T-Con is bad because it got 4x12V on connector and going nowhere else further.

[hacker64]

Re: Sharp LC-46DH77S Communication error? Bad main board?

Hey guys, excuse me for doing that awful UP un the thread, but I have the same problem on same main board.
Branislav18, do you have found which component is faulty? Do you solve the problem?
Thanks

[G3lu]

Re: Sharp LC-46DH77S Communication error? Bad main board?

Hello!Sorry the website administrator but I can not open a discussion for which we did not quite correct! I have a Sharp TV LC20AD5E-BK no longer work at all. We measured a signal diode FCF10A20 as quickly. I replaced it, now TV has sound and sees weak negative image without LCD backlight. I do not know what to check. Please help me with advice, for which I thank you in advance.