Samsung Surveillance LCD

[Josh@GSI]

Hello all, new guy here attempting to fix a Samsung SMT-190DN Surveillance system. I did a search on this forum, and there are only 2 threads that involve this system. I was unable to find information on my issue. I replaced the Caps on the power board and checked all the +5V, +12V and +15V outputs, all good there. I was checking the resistance of the primary and secondary coils in the transformers for the CCFL's. I got no reading (> 1M Ohm) on the secondaries (High voltage side) and less than 1 Ohm on the Primary side (Low voltage side).

The monitor exhibits the 2 seconds then black problem. After the capacitor replacement, still the same problem...

Here are a few pictures to illustrate... I am not sure where to go from here...
Thanks for the help.

[budm]

Re: Samsung Surveillance LCD

Up load straight and closed up pictures of the inverter transformer.
What are the P/N s as printed to the transformer so we can look up the pin out for them?
Do you have ESR meter and capacitance meter to test those two yellow caps on the inverter board?
You may have to build two test lamps so it will be much easier to find out if you do have bad lamps or bad inverter board.
https://www.badcaps.net/forum/showthread.php?t=19987

[selldoor]

Re: Samsung Surveillance LCD

Inverter Board is probably BN44-00118E and I can see some numbers on the transformers
H GT-823 Perhaps NY091568? but cant find one anywhere.
It would be VERY unusual for all 4 to be open so you need to re-test
If we cant find the pin out you will need to do it the long way.
Meter on ohms 2000 with the transformer 2 pins at the top black probe on left top then test each pin going clockwise and report the result in ohms. Hopefully that will give us a clue and we can do shorter tests on the other 3.
There may be lacquer on the pins so you have to scratch down to the solder.

[budm]

Re: Samsung Surveillance LCD

It may be something like this:
http://s807.photobucket.com/user/bud...ml?sort=3&o=12

http://s807.photobucket.com/user/bud...ml?sort=3&o=14

[Josh@GSI]

Re: Samsung Surveillance LCD

Thanks for the replies.

Unfortunately I only have a simple volt/ohm/milliamp meter.

This is a project I took on for work, so when I get home I will take some better pictures for you guys to look at.

[selldoor]

Re: Samsung Surveillance LCD

Meter will be ok perhaps put up a picture of it as well so we dont ask you do do something it wont do.

[Josh@GSI]

Re: Samsung Surveillance LCD

As for the meter, it is a bit old. It was a present to me when I was 5 or 6 (or at least as soon as I learned to do simple math), I am 24 now.

The board is N, GT-823, NY0915CB, BN44-00118F. selldoor, you were very close but here is a better picture as well.

[Josh@GSI]

Re: Samsung Surveillance LCD

Also, here is a still of the monitor on power up... as best as I could do with a phone camera and a very short time frame...

It seems like the backlights flicker a bit, and the top right corner is brighter than the rest of the screen.

[budm]

Re: Samsung Surveillance LCD

You need to get digital meter, and build two test lamps.

[Josh@GSI]

Re: Samsung Surveillance LCD

You need to get digital meter, and build two test lamps.

Yes, a new meter for sure!

as far as building test lamps, what is the best and cheapest way of doing this? I don't really want to invest my own money into something for work.

EDIT: just clicked on your link to using old cf lights....

[Josh@GSI]

Re: Samsung Surveillance LCD

I have not had much time to work on the monitor, but could I get a possible cost of repair? For example, will I need to replace the whole inverter board, or just the transformers? How much do CCFL's usually cost?

[selldoor]

Re: Samsung Surveillance LCD

CCFLs see ccflwarehouse for a clue or on ebay
Cant find transformers on google- maybe look on ebay?
Does this work with a PC llike a normal monitor. If so connect it up and when is goes dark
if the power led stays on can you see a very dim picture of what the PC is outputting
pehaps shining a flashlight at an angle to the screen will help.
If this is a surveillance monitor is it on 24 hours per day - how old is it?
Another thing to try would be to swap the leads around on the inverter board to see if it makes any difference

[Josh@GSI]

Re: Samsung Surveillance LCD

This does work like a PC monitor with a VGA input.
I tried using a flashlight, but the image seems to go away completely when the backlight dies.
I am not sure how old it is, I work for a diesel repair shop and the monitor was for my boss to keep an eye out in the shop.
I will see what happens when I swap some leads around...

[selldoor]

Re: Samsung Surveillance LCD

It is often hard to see the dark picture - important bit (though I didnt say) was Does the Power led stay on when the picture goes off?