Samsung 215tw display cuts out

[Rasta Beuher]

Re: Samsung 215tw display cuts out

Thanks!
When black probe is on the middle, the resistance is 160 ohms from the outer pins. When red probe is on the middle, the resistance is increasing starting from 1 Kohm. The results are the same for the two diodes as the pins are common (I tested onboard).
I am confused, a diode shouldn't be non-passing on a way?

If these components aren't MOSFETs, what is commanding BL on and off? There aren't other 3-pins components in the inverter area. Should I check the integrated circuits on the reverse side of the PCB? If so, how can I do that?

[Rtech]

Re: Samsung 215tw display cuts out

Have just measured one of these out of circuit:-
With the Black lead on centre the Resistance measurement to the outside pins wass 55k ohmHave just measured the same one,OUT od circuit,as follows :-
Meter on Resistance,black on middle,then approx 55K ohms to the outside pins.
Red lead on middle, then 5.5M ohms.
Using the Diode function of the meter,then, Black on the centre then 0.230 on the meter to each outside pins
Red on the centre then Open circuit,as it should be.

The reason for, getting a reading both ways as you did, is due to the filter capacitors on the output of the diodes,being slowly charged as the votage from your meter is applied.

The B/Lights are turned on and off by approx 3-4 volts ,from the Logic board, which finds it way to the Inverter controller,which then activates the lights,via the output transistors,Inverter transformers etc.

[PineCreek]

Re: Samsung 215tw display cuts out

Following the rich information in this thread I've been fixing a 215TW. Unfortunately, I've been unsuccessful at repairing a failed CCFL assembly. I'd like to replace it. I haven't found a direct replacement. Can anyone guide me? Ref post by almoodie giving equivalent screens with same LCD. My model is LTM210M2 and freelander indicates it has same screen as Gateway FPD2185W and HP F2105.

[retiredcaps]

Re: Samsung 215tw display cuts out

I'd like to replace it. I haven't found a direct replacement. Can anyone guide me?

Members here have good feedback regarding ccflwarehouse.com. They sell bare lamps, pre-assembled, and pre-housed options.

Call them and they can help you out.

[kemog]

Re: Samsung 215tw display cuts out

Hello to all!

Very, very helpfull forum.
Same problem as yours (Samsung SyncMaster 215TW) brought me here.

Any progres on the subject? Rasta Beuher?

Mine situation is the same except that I can see pale reflection of Windows desktop (under some angle of view) after monitor is connected to booted PC and on/off button with blue LED (LED light is constant, not blinking) is pressed on the front bezel of monitor. After pressing this button, ~ 10 - 15 seconds, a bright picture of desktop is shown for 0,5 or 1 sec.

After changing all suspected capacitors, I gathered few ideas/solutions:
- bad secondary windings of HV transformers,
- dead CCFL, so that circuit of high voltage is broken and thus turned off,
- or, some of surrounding SMD components connecting inputs and outputs of HV transformers is down (for example small three pins diods/transistors, or smd capacitors or resistors)...


My PSU/inverter board is a little bit different: IP-58130A (NB-20 REV0.2)
Resistance of secondary windings of all transformers is within range of 988 - 991 Ohms. I do not know how to check its inductance (henries).

Please, let reactivate this topic, and help me to narrow down solutions to this problem.

PS:
Can I use shorter CCFLs from another monitors with mounted (borrowed) connectors (2 wider and 2 normal) from this not working Samsung and test inverter part???

[retiredcaps]

Re: Samsung 215tw display cuts out

PS:
Can I use shorter CCFLs from another monitors with mounted (borrowed) connectors (2 wider and 2 normal) from this not working Samsung and test inverter part???

Yes. I have used shorter ccfls for testing.

[kemog]

Re: Samsung 215tw display cuts out - solved

Hello!

I tried with shorter lamps, but could not gather enough of them, only 4 out of 6, and same symptom occurred.

Several users stated that the fix was related to cables of lamps inside the LCD panel.

Since I could not find more then 4 lamps and was getting pretty curious and anxious about this problem I decided to dismantle the panel.

After getting to lamps I discovered same problem as some users mentioned before: two returning lines/wires (thinner wires) were disconnected/desoldered from lamp connector.

I cut away ~0,5 cm of old wire and pulled it form side of plastic connector to make enough of it to be soldered back to lamp.

After doing like this with other lamps I turned on the monitor and light stood on.
I connected the monitor to a PC and left it working for 48 hours with some changeable pictures (screen saver) and with power consumption turned off and concluded that the problem is solved.

Thank you all for putting out yours experiences and ideas about this.
Bye!

[alexanna]

Re: Samsung 215tw display cuts out - solved

Hello!

I tried with shorter lamps, but could not gather enough of them, only 4 out of 6, and same symptom occurred.

Several users stated that the fix was related to cables of lamps inside the LCD panel.

Since I could not find more then 4 lamps and was getting pretty curious and anxious about this problem I decided to dismantle the panel.

After getting to lamps I discovered same problem as some users mentioned before: two returning lines/wires (thinner wires) were disconnected/desoldered from lamp connector.

I cut away ~0,5 cm of old wire and pulled it form side of plastic connector to make enough of it to be soldered back to lamp.

After doing like this with other lamps I turned on the monitor and light stood on.
I connected the monitor to a PC and left it working for 48 hours with some changeable pictures (screen saver) and with power consumption turned off and concluded that the problem is solved.

Thank you all for putting out yours experiences and ideas about this.
Bye!

After you've done a few of this type of repair you will find it's a really simple operation. But sometimes finding the fault can be difficult.

[kemog]

Re: Samsung 215tw display cuts out

Yeah, you're right! After you get into this area steps are a lot easier but every little while there are exceptions with some new design or some small hidden detail which slows you down pretty enough...
But, luckily there are always places like this one badcaps.net, where people are willing to share their knowledge and experience and to help someone!

[Mornagest]

Re: Samsung 215tw display cuts out

Hello,

I got the same issue with the same LCD screen ; according to a reparator, it seems it is an inverter problem, but I'm not sure exactly how to confirm that.

The problem is the same as Almoodie described : when switching the screen on, I get an image for about half a second, then it disappear until I switch it off and on again. The blue light that shows the screen is switched on is still lighted, so could it be a problem from the power board ? Is it still possible to buy a new one somewhere, on Internet ?

I thank you in advance ! (and sorry for my poor English as it isn't my mother tongue)

1) If you get the display to show briefly, it is likely a problem on the inverter board.

2) Do you have a multimeter and know how to measure resistance and voltage?

3) Post clear focused pictures AFTER reading

https://www.badcaps.net/forum/showthread.php?t=1868

4) Please do not post pictures inline as they slow down the loading of pages.

5) For best picture quality and clarity take your boards to a window on a sunny day, turn flash off, and use macro mode. Take a top down view of all your boards (front and back). Make sure the photo is legible so that we can read the PCB printing clearly. A shutter speed of 1/125 or faster will produce nice clear focused pictures. Try to get a photo that is 2000x2000 resolution or as close as possible.

6) Here is an example of the pictures we want.

https://www.badcaps.net/forum/showpo...94&postcount=1

Hello,

After many months of hibernation, I took the time to take some pictures from my cards... here they are, front and rear.

If you need anything else, ask me

Thank you !

[retiredcaps]

Re: Samsung 215tw display cuts out

I took the time to take some pictures from my cards.

The capacitor just left of inverter transformer T303 is bulged.

It looks like all the caps are Capxon. Capxon makes terrible terrible quality caps. See my standard answer on replacing caps (regulars may skip)

https://www.badcaps.net/forum/showpo...84&postcount=3

[Mornagest]

Re: Samsung 215tw display cuts out

Once it is said, it looks obvious... many thanks !

I will try soon to buy a new one ; got a good electonic and electric store not far from my job.

Is there something special to do when soldering ? Got a 50% tin wire, does it fit ?

Thank you once again

[retiredcaps]

Re: Samsung 215tw display cuts out

I will try soon to buy a new one ; got a good electonic and electric store not far from my job.

As long as you have read my link above and understand the risks of NOT replacing all the caps, then go ahead. I'll say it again, Capxon makes terrible quality capacitors

Make sure your store sells "low ESR" caps.

Is there something special to do when soldering ? Got a 50% tin wire, does it fit ?

Good old 60/40 with rosin core flux is my favourite.

[Mornagest]

Re: Samsung 215tw display cuts out

Wow, I just checked the prices... it would be stupid not replacing all the capacitors ! It will cost less than 10 €, wire include...

OK, I will try to buy this tomorrow if I have enough time. And fix this as soon as possible.

Thank you !

[Mornagest]

Re: Samsung 215tw display cuts out

Still doesn't work despite the replacing of all caps (except the largest one). The symptoms are exactly the same : the screen works for two seconds, then turns completely black...

Any idea ?

[selldoor]

Re: Samsung 215tw display cuts out

Hi - Ok - just to check - did you have an input (source) PC
attached?

If it is all connected up can you set up your pc showing
a vivid picture then when you turn on the screen and it has gone black, can you see a faint image on the screen- perhaps shining a torch on it will help.

You may have 2 seconds to black and should read Retiredcaps
guide:https://www.badcaps.net/forum/showthread.php?t=10419

Start at post 19

Next with it all connected take the voltages at the power out connector. Meter on 200vDC Black Probe on Ground screw and then red probe on each pin and record the results.

Please can you also update your profile with Country and Mains Voltage.


Next step will be to test the secondary windings on the inverter transformers - see Plianbills instruction for this in post3

[Mornagest]

Re: Samsung 215tw display cuts out

Hi,

Hi - Ok - just to check - did you have an input (source) PC
attached?

If it is all connected up can you set up your pc showing
a vivid picture then when you turn on the screen and it has gone black, can you see a faint image on the screen- perhaps shining a torch on it will help.

Done ; I see the image as described in the topic.

You may have 2 seconds to black and should read Retiredcaps
guide:https://www.badcaps.net/forum/showthread.php?t=10419

Start at post 19

Now I read it, thank you. Since I have no multimeter at home (but yet at my lab), I will have to wait tuesday to take it back home.

Next with it all connected take the voltages at the power out connector. Meter on 200vDC Black Probe on Ground screw and then red probe on each pin and record the results.

Same as above

Please can you also update your profile with Country and Mains Voltage.

It is done

Next step will be to test the secondary windings on the inverter transformers - see Plianbills instruction for this in post3

OK so the multimeter is really vital !

Thank you for your answer

[selldoor]

Re: Samsung 215tw display cuts out

Hi,

OK so the multimeter is really vital !

Absolutement!

As you have a picture on the dark screen you can skip testing voltages at the voltage out connector..

It looks like it is either a problem with the Inverter Transformers for which you need the meter or a problem with the lamps or the lamp wiring.

[Mornagest]

Finally, I could get a multimeter. What I have done :

1. looked for the MOSFET but I couldn't find it... what a shame... where is it on my board ?
2. measured the resistance of the fuse (I found one, I guess there ain't a second one as nothing else looks like it on the board) : 0,001 Ohm. The fuse seems to be OK.
3. then I measured the resistance between the transformers pins, and I'm also confused ; what do I have to measure, exactly ? Is it the resistance between 1 and 2, 1 and 3, 1 and 4 as shown on the pic ? If this is it, I measured 900 Ohms, 850.000 Omhs and 850.000 Omhs, respectively. Is it normal... ?? This occured for all the six transformers. Guess I did something wrong. Or, the "k" on the multimeter doesn't mean kilo, nor the "M" Mega ?

Sorry to ask such basic questions, but this is the first time I'm trying to fix some electrical material...

Thank you for your answer !

[retiredcaps]

Re: Samsung 215tw display cuts out

[*]then I measured the resistance between the transformers pins, and I'm also confused ; what do I have to measure, exactly ? !

Measure the resistance between S1 and S2 as per

http://www.lcdparts.net/TransformerD...ProductID=3355

Report measurements for all 6 transformer.