Sharp LC-65D64U blinking green LED

[tibimakai]

I have picked up this TV, without stand and remote for $20.
It doesn't turn on, it just blinks the green LED as I plug it in.
If I hold Vol+ and Channel- and the I plug it in, after a few seconds, the Input shows up on the screen, just for a second and then the LED stays on.
I have measured the 12V(-12V) and 60V(-60V) and they are there.
I have measured four FET at the top inverter and four on the bottom inverter, on both sides of the TV. There are, six inverters in total, three on one side and two on the other.
There are two more FET looking components, next to the four FETs, but there are no markings on the PCB, so I'm not sure what kind of components are they.
Two pins seem shorted on all four inverters. So basically at each corner of the TV there are six FET looking components. Four of them are marked with Q which are transistors, but the two next to them are not marked. The case of these transistors are horizontal to the PCB and there is a heatsink on top of them soldered to the board, so the transistor markings are not visible and in the SM, there is no schematic for the inverters.
Anybody has experience with these TVs?
Any help would be appreciated.

[tibimakai]

Re: Sharp LC-65D64U blinking green LED

Somebody had a similar TV, maybe 46" and had very similar issue(maybe the same), but he never updated his thread.
He was talking about two FETs shorted and the other four were OK, but I'm wondering if those two, are really transistors or not. I guess I will have to remove that aluminum heatsink to find out. There are four sets of these 6 FETs at each corner of the TV and at each corner the readings are the same. It would be a weird coincidence, to be all blown out at the same time.
I will have to test the transformers, but there are so many, it will take me a while to test them all.

[mr.mroz88]

Re: Sharp LC-65D64U blinking green LED

I have same problem on my sharp tv
Try this step by step backlight was exactly my problem

If the green power light keeps flashing on and off every second and tv will not power on unplug the tv for 5 minutes, then try this. Keep holding the VOL+ and CH- buttons down while you plug the tv cord back into the wall ac outlet till you get sound and picture for a second or two. You should be able to turn the tv on and off with the power button now. Next turn the power button off and unplug the tv for a few seconds and then plug it back in and turn the power button back on. Watch the screen and see if the sound and picture comes on, best to check in a dark room to see better, if sound stays on and picture comes on a few seconds and back off you have a bad CCFL backlight lamp in the LCD panel.

[tibimakai]

Re: Sharp LC-65D64U blinking green LED

Thanks for the reply.
The first part, I have already done and it acts as you say it does.
I will have to try the second part.
My suspects are, one of the ccfl tubes or one of transformers.
Did you have a bad tube? How did you repaired it? Did you find a tube, at this length?

[mr.mroz88]

Re: Sharp LC-65D64U blinking green LED

No my lamp holders were burned...
I just send it for now and tv works good ... Check my last posts

[tibimakai]

Re: Sharp LC-65D64U blinking green LED

All the contacts are nice and clean.

[tibimakai]

Re: Sharp LC-65D64U blinking green LED

How can I find out, if the tubes are the problem and not the inverters?
It's a huge and very heavy TV, otherwise I would have taken it apart already.

[stj]

Re: Sharp LC-65D64U blinking green LED

visual inspection is the only reliable way to check tubes.
sorry, but having a big tv has costs - getting someplace big enough to open it is one of them!

[tibimakai]

Re: Sharp LC-65D64U blinking green LED

I meant, without opening the panel.

[budm]

Re: Sharp LC-65D64U blinking green LED

Are these the inverter boards?
http://www.shopjimmy.com/catalogsear...harp+LC-65D64U

I see gray fuses on the boards.

[tibimakai]

Re: Sharp LC-65D64U blinking green LED

Great eyes. I haven't even notice them.
TV sits against the workbench, on the floor. Hard to work like that.
I will check them out as soon as I get home.
Thanks Bud.

[budm]

Re: Sharp LC-65D64U blinking green LED

BTW, MROZ88 has the bad pins problem, the lamp sockets are OK, the pins (part of the lamp socket) that make contact with the black sockets on the inverter boards are the problem.
https://www.badcaps.net/forum/showthread.php?t=35737

[tibimakai]

Re: Sharp LC-65D64U blinking green LED

He pointed to me out his problem, but on mine(not the same TV model), I don't have that problem.
I haven't opened up the panel yet. I'm trying to avoid that, if it's possible.

[tibimakai]

Re: Sharp LC-65D64U blinking green LED

All the gray fuses are good.
I have tested all the transformers, at the output side and they are also good, 111-116 Ohm.
Bud, you know anything about the Transistors under the heatsink?
Four out of six seem shorted, but those two may not be transistors, they don't have any markings on the PCB. All six are under the heatsink.
Tomorrow, I will take pictures with these.

[budm]

Re: Sharp LC-65D64U blinking green LED

I cannot say much until I see the pictures. There are so many inverter boards on this TV, one can be bad that will cause it to get error code, or bad lamps, never work on one like this so I cannot tell.

[tibimakai]

Re: Sharp LC-65D64U blinking green LED

Finally I had some time to take the screen apart. It was actually very simple. Screen came off with the metal frame bolted to it, pretty cool.
I have managed to take a picture of the CCFL tubes.
It's only a blink, so it's hard or almost impossible to see what is going on with the naked eye.
In Microsoft Movie Maker I have slowed down the video and at the right time I took a snapshot.
I was surprised on what I have seen. I can't explain it what is going on, I have never had this issue before.
Any ideas?
Far, is left of the screen, near is right, with the switches/ side inputs and LED/sensor board.

[tom66]

Re: Sharp LC-65D64U blinking green LED

It can be misleading to use a single frame like that, the camera can pick up the refresh rate.

However, to me, it looks like only half the bulbs turn on and of them, only half is lit.

This means the slave is probably not working and the master may not be working properly either, however, it's important to note that the master might strobe the bulbs one after another, or only light the other bulbs when the first set have lit.

One common trick is to temporarily disable the error detect on the master so the bulbs will stay on. Then you can power up the set quickly (no more than 10 seconds at a time, watching carefully for parts overheating.) To disable the inverter error detect locate the TIMER pin on the controller chip and bridge the capacitor attached to it.

[tibimakai]

Re: Sharp LC-65D64U blinking green LED

Thanks Tom, I will try it out when I will have a little bit of time.

[tibimakai]

Re: Sharp LC-65D64U blinking green LED

Tom, I can't even tell which one is the master and which one is the slave.
I have made some pictures(most likely not the best), I will upload them a bit later.
It seems, like there is an 8 pin IC 27201.
It could be this one?
http://www.ti.com/product/ucc27201
The side that did not lit up, the inverters are numbered 1, 2, 3. The other side are #4, 5, 6.
#1 & 3 and #4 & 6 have the ICs and transistors on them.

[tibimakai]

Re: Sharp LC-65D64U blinking green LED

OK, here are some pictures, they are not really for diagnostic purposes, just to have an idea how does the TV look like.