black Light problem ln-t4069f

[bandof41]

So I got a TV off a friend, he said it didn't work and he said if I changed the capacitors it'd work again, so I went and I changed the capacitors and it still didn't work.

so I trouble shooted some more and saw that I had a picture on my screen (had to shine a light) and sound, so no black Light. I managed to get a new inverter board off a local guy for cheap and I put that in and still no black Light.

Trouble shooting continued, and I tested all the power, standbys good, power ons good, and the 12v to the inverter was good. Next I took a florescent light and ran it along the high voltage parts and nothing. So I took the inverter board off and checked all the mini transformers, again fine.

I noticed there was a slight noise, almost like a buzz it seemed like it was coming from the bigger transformer on the power supply. I checked the fuse for it (T3,15A250V) it read 709ohm

Then I checked the transformer, tms92267ct, one side read 709ohm and the other 001ohm

So a little help? Should I just replace the full power board? Will I get away with just replacing the fuse? Or maybe the transformer?

Any other information you want, let me know

Here's some pictures https://plus.google.com/100926239867...ts/9xwtYuY4rkN

[ReeceyBurger123]

Re: black Light problem ln-t4069f

Does the bl flash on at all ? If so transformer at fault here if not something else is causing no bl.

[bandof41]

Re: black Light problem ln-t4069f

Yeah the blacklight doesn't come on at all

[bandof41]

Re: black Light problem ln-t4069f

So I noticed that the there's some black on the strips
https://plus.google.com/100926239867...ts/dpr13pyW15C

[budm]

Re: black Light problem ln-t4069f

You have power supply-inverter board combo, P/N BN44-??????
The big long green board connected to the lamp sockets is the Balancer board.

SO: ' I checked the fuse for it (T3,15A250V) it read 709ohm ' are you saying the red fuse shows that much resistance?

[bandof41]

Re: black Light problem ln-t4069f

You have power supply-inverter board combo, P/N BN44-??????
The big long green board connected to the lamp sockets is the Balancer board.

SO: ' I checked the fuse for it (T3,15A250V) it read 709ohm ' are you saying the red fuse shows that much resistance?

Yeah it shows that much, is that wrong?

[bandof41]

Re: black Light problem ln-t4069f

You have power supply-inverter board combo, P/N BN44-??????
The big long green board connected to the lamp sockets is the Balancer board.

SO: ' I checked the fuse for it (T3,15A250V) it read 709ohm ' are you saying the red fuse shows that much resistance?

I stripped back further if you want to see
https://plus.google.com/100926239867...ts/3kQKSDGnNgY

[budm]

Re: black Light problem ln-t4069f

You do have some worn out lamps, the good ones have white coating at the end of the lamps, the worn out one you can see coloration.
It will only take one bad lamp to trip the protection circuit.
Similar setup and test procedure to find out if you have bad lamps:
https://www.youtube.com/watch?v=oE6K4xBVweA

[bandof41]

Re: black Light problem ln-t4069f

You do have some worn out lamps, the good ones have white coating at the end of the lamps, the worn out one you can see coloration.
It will only take one bad lamp to trip the protection circuit.
Similar setup and test procedure to find out if you have bad lamps:
https://www.youtube.com/watch?v=oE6K4xBVweA

How do I tell? They all kind look the same, do you have any references?

[budm]

Re: black Light problem ln-t4069f

Did you watch that video and try making the Voltage measurement yet?
We still do not know the P/N of the power supply-inverter board, BN44-?????

[bandof41]

Re: black Light problem ln-t4069f

Did you watch that video and try making the Voltage measurement yet?
We still do not know the P/N of the power supply-inverter board, BN44-?????

It's a bn44-00167c.

And I'm checking the volts now I had to put the TV back together

[bandof41]

Re: black Light problem ln-t4069f

Did you watch that video and try making the Voltage measurement yet?
We still do not know the P/N of the power supply-inverter board, BN44-?????

I don't know if it's my multi meter but it won't read any AC voltage but for DC the lower have (when being set too 200m) says around 9 till half way up it goes to around 5 for the rest of the way

[budm]

Re: black Light problem ln-t4069f

What DCV do you have on the CNI806 on the power supply board after the power switch is turned on?
PIN 1 VCC_12V = ????
PIN 5 LD (Lamp Detect) = ??????

[budm]

Re: black Light problem ln-t4069f

I don't know if it's my multi meter but it won't read any AC voltage but for DC the lower have (when being set too 200m) says around 9 till half way up it goes to around 5 for the rest of the way

Per Video, there are many test points on the balancer board that you need to check to see if one of the lamp has trigger the protection circuit, so I have no idea which one is giving you the reading you have indicated.

[budm]

Re: black Light problem ln-t4069f

So now we know what the P/N of the board is, see the diagram attached (REV B), since the Backligts did not even flash on for seconds then we need to look at the inverter section.
BTW, ALL the fuses are OK, especially fuse FI801 for the Inverter circuit.
You should also veirfy thatyou do have >380VDC at both ends of the fuse FI801 with ref to the negative leg of the main filter cap.
http://www.shopjimmy.com/samsung-bn4...pply-unit.htm#