Samsung LN46B610

[Malachi]

Just got this free. Not as nice as the Panasonic plasma tvs that some on here are getting free. Lol

When power is applied to the tv, it chimes and the font led comes on. Nothing on screen ever.
Pressing button on the remote causes the front red LED to flicker.
Voltage between the two main capacitors is steady 388v with the mainboard disconnected. With it connected it sits at 168v.

Also with the mainboard disconnected the backlights flash on briefly.

The original owner tried changing the tcon but said it didn't help. I have both tcons and it doesn't affect anything.
Does it look like a mainboard problem?

Not sure how to force the backlights to stay on on this. I haven't worked on a ccfl tv before.

[budm]

Re: Samsung LN46B610

Pictures, pictures, pictures?
What DCV have you checked on the power supply connector that goes to the main board?

[Malachi]

Re: Samsung LN46B610

Sorry, I uploaded the wrong picture.
I get 5v where it asks for it and 13v where it asks for it.

[Malachi]

Re: Samsung LN46B610

Mainboard picture.

[dick_barton]

Re: Samsung LN46B610

Can you jumper inv_on to 5V with the mainboard disconnected to bring on the lamps?

[Malachi]

Re: Samsung LN46B610

I can try. The lights flash on with the mainboard disconnected but I will try in a few.
They don't stay on. The just flash when I jump the 2.

[dick_barton]

Re: Samsung LN46B610

I bought a CCFL tester which has proved very useful for quickly checking the tubes.

http://tinyurl.com/hlvnl9p

It may be worth your while checking the joints around the transformers on the inverter boards for cracked joints.

[Malachi]

Re: Samsung LN46B610

When you ask me to jump the inv_on to 5V should I live the mainboard connector connected into the psu and disconnected the other end from the mainboard?
Or disconnect it at the psu end?

Solder joints on the inverter look good.

[dick_barton]

Re: Samsung LN46B610

It's purley guesswork on my part and I don't know if it will work but suggesting you try with the mainboard disconnected from the power supply. You said in an earlier post that all your supplies were up. If they are not when the mainboard is disconnected then you will also need to jumper PS_On to 5Vstby

You can disconnect it at the mainboard because I find it easier to place the jumper resistors into the floating connector.

[dick_barton]

Re: Samsung LN46B610

Solder joints on the inverter look good.

Another test often asked for is to measure the resistance of the inverter transformers and check that they are within 3% of each other.

[Malachi]

Re: Samsung LN46B610

Jump it with a resistor? I was only using a wire. Oops.
Just tried wit a 1k resister, same outcome. Backlights just flash once.

[dick_barton]

Re: Samsung LN46B610

A resistor just so that you don't short circuit anything and limits the current in the event that you do.

[Malachi]

Re: Samsung LN46B610

Inv-on is 3.7v when I leave the power plugged in. When I first apply power to the tv, it reads about 4.4, that's when the lights flash.
This is without the resistor in place.

I just noticed that when I reconnect the mainboard, the backlights flash on when I turn the tv off, instead at coming on when I plug the power in with mainboard disconnected.

[budm]

Re: Samsung LN46B610

What is the power supply/iNVERTER Combo board board P/N? BN44-?????
The big long board attached to the lamps is the Balancer board.

[Malachi]

Re: Samsung LN46B610

It's BN44-00265B.

[Malachi]

Re: Samsung LN46B610

Fixed the tv. Thanks for all the help. Nothing to see here.
Move along please.

[dick_barton]

Re: Samsung LN46B610

What was the solution out of interest?

[Malachi]

Re: Samsung LN46B610

If you look at the top right of the psu/inverter, you will see a connector with out a plug in it but wires going to it?
I hadn't noticed that at first. The previous owner worked on it but must have forgotten to reconnect it. The plug was stuck behind the connector, with the wires leading right to it, so I didn't notice.

Not bad for free.

[dick_barton]

Re: Samsung LN46B610

It's not often you get this sort of luck. Good on you.

[budm]

Re: Samsung LN46B610

That connector is for receiving the the FB signal (Feedback AC milliVolt range, lamps' current used for maintaining lamp brightness), LD signal (Lamp detection to verify if the lamp is connected or stays conduct after firing Voltage is applied, >11VDC = Normal, <10v = Bad), feeds the VCC_12V (to run the detection circuit) on the Balancer board.