Sharp LC-40LE810UN question

[tibimakai]

Re: Sharp LC-40LE810UN question

No voltages are present, except some milivolts on the LB connector either.

[tom66]

Re: Sharp LC-40LE810UN question

Yeah, so the problem is likely with the main power supply; check these locations.

RED - Test resistance (power off)
GREEN - Check voltage across (power on)
1. should be around 10V to 15V
2. should be around 115V AC (use AC scale)

If red is OPEN, then the FET is probably short.

If GREEN 1 is low, then the startup cap, charge resistor or a diode on the secondary is short.

If GREEN 2 is low, then AC is not getting to the right part for some reason.

[budm]

Re: Sharp LC-40LE810UN question

It looks like PD-11 (BU5V) may be the STBY5V.
Need to see the back side of the board to make more sense.

[tibimakai]

Re: Sharp LC-40LE810UN question

That is another possibility.
I will take some photos and measure tom's voltages in the afternoon.


Bud could you please express your opinion about that 37" Samsung with the T-con problem? Not sure to complain about the board or just let go this TV.

[tibimakai]

Re: Sharp LC-40LE810UN question

OK, here are the measurements:
Red resistor is OK=19.4K
Green #1= 5.5V
Green #2= ~62.6V
I have made some pictures too:

[budm]

Re: Sharp LC-40LE810UN question

What is that Green #2, I do not see the connections on the bottom side of the board. And how did you access to measure the voltage on it?
The 19K resistor is for the Snubber circuits.
Can I get pictures of the area in red? I see some traces have corrosion (dark stain).

[tibimakai]

Re: Sharp LC-40LE810UN question

I have disconnected the two LED connectors and held it vertically.
I will put up some more pictures later on from that area.
There is some corrosion, the tuner for example it's rusted completely.
I'm going to pick up another LG now.
Here it is the Green#2:

[budm]

Re: Sharp LC-40LE810UN question

But that is GAS discharge tube, that black thing looks like a black rubber bumper. If that is the two points you have measure 62.5VAC, that cannot not be right since that part is in parallel with one of the common mode choke (very low DC resistance, and low reactive reactance) winding, the voltage will be less than 1VAC. You can also see that they did not install another GT on the top section of the choke either.

[tibimakai]

Re: Sharp LC-40LE810UN question

They actually look and feel like rubber layers on top of each other.
I will take those measurements in the morning.

[budm]

Re: Sharp LC-40LE810UN question

I think that is just a rubber bumper, I do not believe they stuff the GTxxx in those two locations on the board. The main thing is the AC reading of 60 something VAC at those two pads, it cannot be that high at all.

[tibimakai]

Re: Sharp LC-40LE810UN question

I have to measure between the two pins or from main caps negative and pin?

[tom66]

Re: Sharp LC-40LE810UN question

What is the marking on the resistor? I was expecting it to be a fusible resistor, but it could be a snubber too.

[tom66]

Re: Sharp LC-40LE810UN question

Those spark gaps are one of the devices that make the crackling sounds when you plug something in due to the inductor voltage building up rapidly (intermittent contact.)

[tibimakai]

Re: Sharp LC-40LE810UN question

Actually that traf has to be measured vertically and that way shows at both in/out 117VAC.
That resistor is 20Kohm/2WAT.

Just sold two TVs in an hour=$600 total, yeeaahhhh!!

[tibimakai]

Re: Sharp LC-40LE810UN question

I wrote down the ICs markings, and I have found two of them, but not the other three.
The one that I have found is: DDA002C and 1608B.
There are other three ICs which I haven't found yet anything, these are:
DDA003A, 36S3LJ/G1006, 5209/50YS005
For the 1608B here is the datasheet:
http://www.datasheetarchive.com/IC+1...datasheet.html
For the DDA002C I have found some pictures:

[tibimakai]

Re: Sharp LC-40LE810UN question

Any more ideas?

[tom66]

Re: Sharp LC-40LE810UN question

Voltage across green #1 is too low, check the IC near to it, and see if you can get part #.

[tibimakai]

Re: Sharp LC-40LE810UN question

3BS3LJ/G1006
https://cdn.badcaps-static.com/pdfs/...168ebf91ad.pdf

[tom66]

Re: Sharp LC-40LE810UN question

Page 5: "The VCC pin is the positive supply of the IC. The operating range is between 10.5V and 26V."

Check for shorted diodes on the output. Does the supply click or tick at all, approximately a few times a second?

[tibimakai]

Re: Sharp LC-40LE810UN question

It's completely dead. I will measure those voltages in the morning, here is 12:00AM.