Please help with Samsung Syncmaster 2333SW CCFL Bulbs

[LDSisHere]

Can someone please help me figure out what CCFL bulbs I need to order for a Samsung Syncmaster 2333SW with a INNOLUX MT230DW01 V.0 screen?

I started troubleshooting this monitor a few months ago but quickly discovered that I did not have enough tools to do the job properly, however things have improved. I was able to do a proper job of troubleshooting the problem was two bad CCFL bulbs. I disassembled the screen down to the bulbs hoping to find a bad solder job, Instead I found both bulbs with a scorched mark about an inch from the end and pieces missing. I have never taken an LCD screen down to this level, nor ordered bulbs for one, so as soon as I found the problem I reassembled it until I sourced replacements.

I figured were ordered by screen make and model, so it was only when I was looking online that I realized I needed the bulb length and diameter that I did not have. I am hoping someone on this board may know what it is that I need for this screen. I do not have to risk damage by taking it apart just for the measurements if I can help it. Also, recommendations for good places to source these bulbs would be helpful.

Thank for reading.
Lloyd

[retiredcaps]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

Also, recommendations for good places to source these bulbs would be helpful.

https://www.badcaps.net/forum/showpo...3&postcount=12

[budm]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

http://www.lcdparts.net/howto/selectccfl.aspx

[tibimakai]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

Bad tubes hmm? I have a 2333HD that doesn't start, I should take it apart to see the tubes.

[LDSisHere]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

Thanks, that looks like what I needed to know. I will try ordering some and I will see if can manage to install them without breaking them. They seem very fragile.

[retiredcaps]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

I will try ordering some and I will see if can manage to install them without breaking them. They seem very fragile.

50% of the people who attempt this repair fail because they rush the job or get frustrated.

[Lumberjack777]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

Thanks, that looks like what I needed to know. I will try ordering some and I will see if can manage to install them without breaking them. They seem very fragile.

They are. Once I was relamping, and was looking at the LCD screen, and set some needlenose pliers down on the bench. Right on top of a bulb. *crack* Oops!
Also, the LCD screen at some point will be free and loose. Don't let it fall, or pry against it. One tiny little chip, or crack, and that's all she wrote.
And one last thing; the plastic diffusers. Keep them in the exact same order and orientation, and check for dust, hair, or fingerprints and blow it off or clean them before reassembly.

50% of the people who attempt this repair fail because they rush the job or get frustrated.

Yes, it's totally a finesse job. An operation. Expect it to take a couple hours. And if you manage to do it in less time. Great.

[tibimakai]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

In mine the tubes don't look bad. They don't light up at all, but all PS voltages are fine. Traf measures at the secondary windings: 1028 OHM and 1032 Ohm. I have picture if I check with a flashlight.
Most likely inverter problem. At the bottom has a STU312D.
I can hear a buzz though. Not sure from where is coming from, and I don't have a high precision tube for listening(kidding).

[tibimakai]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

Anybody has any input?

[budm]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

Any pictures and also try another set of test lamps just to be sure?

[tibimakai]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

I have tried from an LG 22" and it's the same, a no go.
I will take pictures as soon as a can.
On these little things there are no fuses on the inverter side?

[tibimakai]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

The capacitors are on the way from Digikey.
Here are the pictures:
(left side inverter, right side connector for the main board)
This is the 2333HD version, has a big mainboard.

[budm]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

So are you getting any voltage at the small green fuse for the inverter circuit? There is only one Dual MOSFETs that drive the transformer (it is a half bridge drive setup), chek all the pins of the MOSFET to see if there are any voltage on them. P/N of the MOSFET and the PWM IC?
Also on the white connector to the main board , I cannot read which pin is for the BL_ON pin, see if it has >3V on that pin.

[tibimakai]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

I'm writing from work, so I don't have all the info, but the FET is a STU312D.
I haven't measured the voltage at the fuse, but the fuse it's OK, I will check it.
The PWM IC is the biggest next to the FET, right?

[budm]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

The PWM IC is the one with 20 pins (I think, or 18 pins).

[tibimakai]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

Unfortunately, I can't read the part number from the IC. I did not had time to measure the voltages yet.
This is all I can see:

[tibimakai]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

I have measured the STU312D.
I'm confused where should I put the black probe.
I haved measured both ways.
I was measuring from left to right with the tab pointing up.
From secondary ground I'm getting:
pin#1= -0.019V
pin#2= 1.3V
tab= -9.57V
pin#4= 16.22V
pin#5= 13.89V
From primary ground I'm getting:
pin#1= 73.2V
pin#2= 74.6V
tab= 82.8V
pin#4= 89.4V
pin#5= 87V
Main cap voltage is: 149.5V

[tibimakai]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

Any input?

[tibimakai]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

Still no help

[budm]

Re: Please help with Samsung Syncmaster 2333SW CCFL Bulbs

"From secondary ground I'm getting:
pin#1= -0.019V
pin#2= 1.3V
tab= -9.57V
pin#4= 16.22V
pin#5= 13.89V"

OK, the gates of the MOSFETs are not getting any drive signal from the PWM IC